Sensitive detection and precise quantitation of trace-level crucial biomarkers in a complex sample matrix has become an important area of research.For example,the detection of high-sensitivity cardiac troponin I (hs-c...Sensitive detection and precise quantitation of trace-level crucial biomarkers in a complex sample matrix has become an important area of research.For example,the detection of high-sensitivity cardiac troponin I (hs-cTnI) is strongly recommended in clinical guidelines for early diagnosis of acute myocardial infarction.Based on the use of an electrode modified by single-walled carbon nanotubes (SWCNTs) and a Ru(bpy)32+-doped silica nanoparticle (Ru@SiO2)/tripropylamine (TPA) system,a novel type of electrochemiluminescent (ECL) magnetoimmunosensor is developed for ultrasensitive detection of hs-cTnI.In this approach,a large amount of[Ru(bpy)3]2+is loaded in SiO2(silica nanoparticles) as luminophores with high luminescent efficiency and SWCNTs as electrode surface modification material with excellent electrooxidation ability for TPA.Subsequently,a hierarchical micropillar array of microstructures is fabricated with a magnet placed at each end to efficiently confine a single layer of immunomagnetic microbeads on the surface of the electrode and enable 7.5-fold signal enhancement In particular,the use of transparent SWCNTs to modify a transparent ITO electrode provides a two-order-of-magnitude ECL signal amplification.A good linear calibration curve is developed for hs-cTnI concentrations over a wide range from 10 fg/ml to 10 ng/ml,with the limit of detection calculated as 8.720 fg/ml (S/N=3).This ultrasensitive immunosensor exhibits superior detection performance with remarkable stability,reproducibility,and selectivity.Satisfactory recoveries are obtained in the detection of hs-cTnI in human serum,providing a potentia analysis protocol for clinical applications.展开更多
The aim of this study was to explore the associations of moderate-to-vigorous-intensity physical activity(MVPA)time and sedentary(SED)time with a history of cardiovascular disease(CVD)and multifactorial(i.e.,blood pre...The aim of this study was to explore the associations of moderate-to-vigorous-intensity physical activity(MVPA)time and sedentary(SED)time with a history of cardiovascular disease(CVD)and multifactorial(i.e.,blood pressure(BP),body mass index(BMI),low-density lipoprotein cholesterol(LDL-C),and glycated hemoglobin A1c(HbA1c))control status among type 2 diabetes mellitus(T2DM)patients in China.A cross-sectional analysis of 9152 people with type 2 diabetes from the Multifactorial Intervention on Type 2 Diabetes(MIDiab)study was performed.Patients were grouped according to their self-reported MVPA time(low,<150 min·week−1;moderate,150 to<450 min·week−1;high,≥450 min·week−1)and SED time(low,<4 h·d–1;moderate,4 to<8 h·d–1;high,≥8 h·d–1).Participants who self-reported a history of CVD were identified as having a CVD risk.Odds ratios(ORs)and 95%confidence intervals(CIs)of CVD risk and multifactorial control status associated with MVPA time and SED time were estimated using mixed-effect logistic regression models,adjusting for China’s geographical region characteristics.The participants had a mean±standard deviation(SD)age of(60.87±8.44)years,44.5%were women,and 25.1%had CVD.After adjustment for potential confounding factors,an inverse association between high MVPA time and CVD risk that was independent of SED time was found,whereas this association was not observed in the moderate-MVPA group.A higher MVPA time was more likely to have a positive effect on the control of BMI.Compared with the reference group(i.e.,those with MVPA time≥450 min·week−1 and SED time<4 h·d–1),CVD risk was higher in the low-MVPA group:The OR associated with an SED time<4 h·d–1 was 1.270(95%CI,1.040–1.553)and that associated with an SED time≥8 h·d–1 was 1.499(95%CI,1.149–1.955).We found that a high MVPA time(i.e.,≥450 min·week−1)was associated with lower odds of CVD risk regardless of SED time among patients with T2DM.展开更多
Intrinsic electric-magnetic property and special nano-micro architecture of functional materials have a significant effect on its electromagnetic wave energy conversion,especially in the microwave absorption(MA) field...Intrinsic electric-magnetic property and special nano-micro architecture of functional materials have a significant effect on its electromagnetic wave energy conversion,especially in the microwave absorption(MA) field.Herein,porous Ni1-xCox@Carbon composites derived from metal-organic framework(MOF)were successfully synthesized via solvothermal reaction and subsequent annealing treatments.Benefiting from the coordination,carbonized bimetallic Ni-Co-MOF maintained its initial skeleton and transformed into magnetic-carbon composites with tunable nano-micro structure.During the thermal decomposition,generated magnetic particles/clusters acted as a catalyst to promote the carbon sp^2 arrangement,forming special core-shell architecture.Therefore,pure Ni@C microspheres displayed strong MA behaviors than other Ni1-xCox@Carbon composites.Surprisingly,magnetic-dielectric Ni@C composites possessed the strongest reflection loss value-59.5 dB and the effective absorption frequency covered as wide as 4.7 GHz.Meanwhile,the MA capacity also can be boosted by adjusting the absorber content from 25% to 40%.Magnetic-dielectric synergy effect of MOF-derived Ni1-xCox@Carbon microspheres was confirmed by the off-axis electron holography technology making a thorough inquiry in the MA mechanism.展开更多
Different switching frequencies are required when SiC metal-oxide-semiconductor field-effect transistors(MOSFETs)are switching in a space environment.In this study,the total ionizing dose(TID)responses of SiC power MO...Different switching frequencies are required when SiC metal-oxide-semiconductor field-effect transistors(MOSFETs)are switching in a space environment.In this study,the total ionizing dose(TID)responses of SiC power MOSFETs are investigated under different switching frequencies from 1 kHz to 10 MHz.A significant shift was observed in the threshold voltage as the frequency increased,which resulted in premature failure of the drain-source breakdown voltage and drain-source leakage current.The degradation is attributed to the high activation and low recovery rates of traps at high frequencies.The results of this study suggest that a targeted TID irradiation test evaluation method can be developed according to the actual switching frequency of SiC power MOSFETs.展开更多
In order to solve the problem of high computing cost and low simulation accuracy caused by discontinuity of incision in traditional meshless model,this paper proposes a soft tissue deformation model based on the Marqu...In order to solve the problem of high computing cost and low simulation accuracy caused by discontinuity of incision in traditional meshless model,this paper proposes a soft tissue deformation model based on the Marquardt algorithm and enrichment function.The model is based on the element-free Galerkin method,in which Kelvin viscoelastic model and adjustment function are integrated.Marquardt algorithm is applied to fit the relation between force and displacement caused by surface deformation,and the enrichment function is applied to deal with the discontinuity in the meshless method.To verify the validity of the model,the Sensable Phantom Omni force tactile interactive device is used to simulate the deformations of stomach and heart.Experimental results show that the proposed model improves the real-time performance and accuracy of soft tissue deformation simulation,which provides a new perspective for the application of the meshless method in virtual surgery.展开更多
Technological advancements in recent decades have greatly transformed the field of material chemistry.Juxtaposing the accentuating energy demand with the pollution associated,urgent measures are required to ensure ene...Technological advancements in recent decades have greatly transformed the field of material chemistry.Juxtaposing the accentuating energy demand with the pollution associated,urgent measures are required to ensure energy maximization,while reducing the extended experimental time cycle involved in energy production.In lieu of this,the prominence of catalysts in chemical reactions,particularly energy related reactions cannot be undermined,and thus it is critical to discover and design catalyst,towards the optimization of chemical processes and generation of sustainable energy.Most recently,artificial intelligence(AI)has been incorporated into several fields,particularly in advancing catalytic processes.The integration of intensive data set,machine learning models and robotics,provides a very powerful tool in modifying material synthesis and optimization by generating multifarious dataset amenable with machine learning techniques.The employment of robots automates the process of dataset and machine learning models integration in screening intermetallic surfaces of catalyst,with extreme accuracy and swiftness comparable to a number of human researchers.Although,the utilization of robots in catalyst discovery is still in its infancy,in this review we summarize current sway of artificial intelligence in catalyst discovery,briefly describe the application of databases,machine learning models and robots in this field,with emphasis on the consolidation of these monomeric units into a tripartite flow process.We point out current trends of machine learning and hybrid models of first principle calculations(DFT)for generating dataset,which is integrable into autonomous flow process of catalyst discovery.Also,we discuss catalyst discovery for renewable energy related reactions using this tripartite flow process with predetermined descriptors.展开更多
Nanomaterials with strong near-infrared absorption and high photothermal conversion ability have shown great application potential in many areas including cancer treatment.However,the current photothermal conversion n...Nanomaterials with strong near-infrared absorption and high photothermal conversion ability have shown great application potential in many areas including cancer treatment.However,the current photothermal conversion nanomaterials generally have poor biodegradability and would stay in展开更多
The Mesozoic intrusions of the Jiaodong Peninsula,eastern China,host giant gold deposits.Understanding the genesis of these deposits requires the determination of the source of the parental auriferous fluid and the ti...The Mesozoic intrusions of the Jiaodong Peninsula,eastern China,host giant gold deposits.Understanding the genesis of these deposits requires the determination of the source of the parental auriferous fluid and the timing of gold mineralization,which are strongly influenced by the cooling/uplift histories of the hosting intrusions.We performed an integrated U-Pb geochronology study on both zircon and apatite from four major magmatic episodes of the Jiaodong Peninsula.The zircon and apatite U-Pb ages are 156.9±1.2 and 137.2±2.4 Ma for the Linglong intrusion,129.9±1.0 and 125.0±3.8 Ma for the Qujia intrusion,119.5±0.7 and 117.2±1.8 Ma for the Liulinzhuang intrusion,118.6±1.0 and 111.6±1.6 Ma for the Nansu intrusion,respectively.The coupled zircon and apatite data of these granitoids indicate a slow cooling rate(11.9°C/Ma)in the Late Jurassic,and rapid uplift and cooling(35.8-29.2°C/Ma)in the Early Cretaceous.The dramatically increased uplift and cooling period in the Early Cretaceous are contemporaneous with large-scale gold mineralization in the Jiaodong Peninsula.This implies that thermal upwelling of asthenosphere and related tectonic extension played an important role in gold remobilization and precipitation.展开更多
Studies have found a U-shaped relationship between sleep duration and chronic kidney disease(CKD)risk,but limited research evaluated the association of reallocating excessive sleep to other behavior with CKD.We includ...Studies have found a U-shaped relationship between sleep duration and chronic kidney disease(CKD)risk,but limited research evaluated the association of reallocating excessive sleep to other behavior with CKD.We included 104538 participants from the nationwide cohort of the Risk Evaluation of Cancers in Chinese Diabetic Individuals:A Longitudinal Study,with self-reported time of daily-life behavior.Using isotemporal substitution models,we found that substituting 1 h of sleeping with sitting,walking,or moderate-to-vigorous physical activity was associated with a lower CKD prevalence.Leisure-time physical activity displacement was associated with a greater prevalence reduction than occupational physical activity in working population.In stratified analysis,a lower CKD prevalence related to substitution toward physical activity was found in long sleepers.More pronounced correlations were observed in long sleepers with diabetes than in those with prediabetes,and they benefited from other behavior substitutions toward a more active way.The U-shaped association between sleep duration and CKD prevalence implied the potential effects of insufficient and excessive sleep on the kidneys,in which the pernicious link with oversleep could be reversed by time reallocation to physical activity.The divergence in the predicted effect on CKD following time reallocation to behavior of different domains and intensities and in subpopulations with diverse metabolic statuses underlined the importance of optimizing sleeping patterns and adjusting integral behavioral composition.展开更多
A novel strategy is proposed to directly synthesize water-soluble hexagonal NaYF4 nanorods by doping rare-earth ions with large ionic radius (such as La^(3+), Ce^(3+), Pr^(3+), Nd^(3+), Sm^(3+), Eu^(3+), and Gd^(3+)),...A novel strategy is proposed to directly synthesize water-soluble hexagonal NaYF4 nanorods by doping rare-earth ions with large ionic radius (such as La^(3+), Ce^(3+), Pr^(3+), Nd^(3+), Sm^(3+), Eu^(3+), and Gd^(3+)), and the dopant- controlled growth mechanism is studied. Based on the doping effect, we fabricated water-soluble hexagonal NaYF4:(Yb,Er)/La and NaYF4:(Yb,Er)/Ce nanorods, which exhibited much brighter upconversion fluorescence than the corresponding cubic forms. The sizes of the nanorods can be adjusted over a broad range by changing the dopant concentration and reaction time. Furthermore, we successfully demonstrated a novel depth-sensitive multicolor bioimaging for in vivo use by employing the as-synthesized NaYF4:(Yb,Er)/La nanorods as probes.展开更多
Chiglitazar(Carfloglitazar)is a novel peroxisome proliferator-activated receptor(PPAR)pan-agonist that has shown promising effects on glycemic control and lipid regulation in patients with type 2 diabetes.In this rand...Chiglitazar(Carfloglitazar)is a novel peroxisome proliferator-activated receptor(PPAR)pan-agonist that has shown promising effects on glycemic control and lipid regulation in patients with type 2 diabetes.In this randomized phase 3 trial,we compared the efficacy and safety of chiglitazar with sitagliptin in patients with type 2 diabetes who had insufficient glycemic control despite a strict diet and exercise regimen.Eligible patients were randomized(1:1:1)to receive chiglitazar 32 mg(n=245),chiglitazar 48 mg(n=246),or sitagliptin 100 mg(n=248)once daily for 24 weeks.The primary endpoint was the change in glycosylated hemoglobin A_(1C)(HbA_(1c))from baseline at week 24 with the non-inferiority of chiglitazar over sitagliptin.Both chiglitazar and sitagliptin significantly reduced HbA1c at week 24 with values of-1.40%,-1.47%,and-1.39%for chiglitazar 32 mg,chiglitazar 48 mg,and sitagliptin 100 mg,respectively.Chiglitazar 32 and 48 mg were both non-inferior to sitagliptin 100 mg,with mean differences of-0.04%(95%confidential interval(Cl)-0.22 to 0.15)and-0.08%(95%Cl-0.27 to 0.10),respectively.Compared with sitagliptin,greater reduction in fasting and 2-h postprandial plasma glucose and fasting insulin was observed with chiglitazar.Overall adverse event rates were similar between the groups.A small increase in mild edema in the chiglitazar 48 mg group and slight weight gain in both chiglitazar groups were reported.The overall results demonstrated that chiglitazar possesses good efficacy and safety profile in patients with type 2 diabetes inadequately controlled with lifestyle interventions,thereby providing adequate supporting evidence for using this PPAR pan-agonist as a treatment option for type 2 diabetes.展开更多
Carbon-sulfur composites have draw n in creasing interest in various fields including electrocatalysis because of their unique structures.However,carb on-sulfur composite with tiny sulfur nano crystals has still recei...Carbon-sulfur composites have draw n in creasing interest in various fields including electrocatalysis because of their unique structures.However,carb on-sulfur composite with tiny sulfur nano crystals has still received little attention.Herein,hollow porous carb on sphere-sulfur composite(HPCS-S)which possesses excellent electrochemical performance towards H2O2 has been prepared for the first time via a simple silica template method.The 2-5 nm sulfur nan ocrystals being restricted in the cha nnel of the hollow porous carb on spheres are un der a strong compressive stress,which was further con firmed by high-resoluti on tran smissi on electr on microscopy(HRTEM)and GPA.The HPCS-S nano crystals show better con ductivity tha n amorphous sulfur clusters because of the reducti on of the steric hindrance which efficie ntly promotes the electron transportation.Consequently,the higher activity and selectivity towards the 2e^oxygen reduction reaction(ORR)to H2O2 in alkaline solution was obtained.The H2O2 selectivity rises from 20%to over 70%after the sulfur addition and the H2O2 production rate achieves 183.99 mmol-gcataiyst-1 with the Faradaic efficiency of 70%.Furthermore,performance enhancement mechanism was also investigated using the den sity functional theory(DFT)calculatio ns.After the in troduci ng of sulfur nano crystals,the appeara nee of S-S bond greatly decreases the overpotential compared with S-doping,which results in significant enhancement of the electrocatalytic property.Consequently,the HPCS-S can be an efficient H2O2 production electrocatalyst in alkaline solution.展开更多
The nanoscale core/shell heterostructure is a particularly efficient motif to combine the promising properties of plasmonic materials and rare-earth compounds; however, there remain significant challenges in the synth...The nanoscale core/shell heterostructure is a particularly efficient motif to combine the promising properties of plasmonic materials and rare-earth compounds; however, there remain significant challenges in the synthetic control due to the large interfacial energy between these two intrinsically unmatched materials. Herein, we report a synthetic route to grow rare-earth-vanadate shells on gold nanorod (AuNR) cores. After modifying the AuNR surface with oleate through a surfactant exchange, well-packaged rare-earth oxide (e.g., Gd2O3:Eu) shells are grown on AuNRs as a result of the multiple roles of oleate. Furthermore, the composition of the shell has been altered from oxide to vanadate (GdVO4:Eu) using an anion exchange method. Owing to the carefully designed strategy, the AuNR cores maintain the morphology during the synthesis process; thus, the final Au/GdVO4: Eu core/shell NRs exhibit strong absorption bands and high photothermal efficiency. In addition, the Au/GdVO4:Eu NRs exhibit bright Eu^3+ fluorescence with quantum yield as high as -17%; bright Sm^3+ and Dy^3+ fluorescence can also be obtained by changing the lanthanide doping in the oxide formation. Owing to the attractive integration of the plasmonic and fluorescence properties, such core/shell heterostructures will find particular applications in a wide array of areas, from biomedicine to energy.展开更多
Design and fabrication of cost-effective transition metal and their oxides-based nanocomposites are of paramount significance for metal-air batteries and water-splitting.However,the traditional optimized designs for n...Design and fabrication of cost-effective transition metal and their oxides-based nanocomposites are of paramount significance for metal-air batteries and water-splitting.However,the traditional optimized designs for nanostructure are complicated,low-efficient and underperform for wide-scale applications.Herein,a novel hierarchical framework of hollow Ni/NiFe2O4-CNTs compositemicrosphere forcibly-assembled by zero-dimensional(OD)Ni/NiFo204 nanoparticle(<16 nm)and one-dimensional(1D)self-supporting CNTs was fabricated successfully.Benefitted from the unique nanostructure,such monohybrids can achieve remarkable oxygen evolution reaction(OER)performance in alkaline media with a low overpotential and superior durability,which exceeds most of the commercial catalysts based on IrO/RuO2 or other non-noble metal nanomaterials.The enhanced OER performance of Ni/NiFe2OA-CNTs composite is mainly ascribed to the increased catalytic activity and the optimized conductivity induced by the effects of strong hierarchical coupling and charge transfers between CNTs and Ni/NiFe204 nanoparticles.These effects are greatly boosted by the polarized heterojunction interfaces confirmed by electron holography.The density functional theory(DFT)calculation indicates the epitaxial Ni further enriches the intrinsic electrons contents of NiFe204 and thus accelerates absorption/desorption kinetics of OER intermediates.This work hereby paves a facile route to construct the hollow composite microsphere with excellent OER electrocatalytic activity based on non-noble metal oxide/CNTs.展开更多
Shape-morphing hydrogels can be widely used to develop artificial muscles,reconfigurable biodevices,and soft robotics.However,conventional approaches for developing shape-morphing hydrogels highly rely on composite ma...Shape-morphing hydrogels can be widely used to develop artificial muscles,reconfigurable biodevices,and soft robotics.However,conventional approaches for developing shape-morphing hydrogels highly rely on composite materials or complex manufacturing techniques,which limit their practical applications.Herein,we develop an unprecedented strategy to edit the shape morphing of monocomponent natural polysaccharide hydrogel films via integrating gradient cross-linking density and geometry effect.Owing to the synergistic effect,the shape morphing of chitosan(CS)hydrogel films with gradient cross-linking density can be facilely edited by changing their geometries(length-to-width ratios or thicknesses).Therefore,helix,short-side rolling,and longside rolling can be easily customized.Furthermore,various complex artificial 3D deformations such as artificial claw,horn,and flower can also be obtained by combining various flat CS hydrogel films with different geometries into one system,which can further demonstrate various shape transformations as triggered by pH.This work offers a simple strategy to construct a monocomponent hydrogel with geometry-directing programmable deformations,which provides universal insights into the design of shape-morphing polymers and will promote their applications in biodevices and soft robotics.展开更多
Gold nanoparticles(AuNPs) have been attractive for nanomedicine because of their pronounced optical properties.Here,we customerized the methods to synthesize two types of gold nanostars,Au nanostars-1 and Au nanostars...Gold nanoparticles(AuNPs) have been attractive for nanomedicine because of their pronounced optical properties.Here,we customerized the methods to synthesize two types of gold nanostars,Au nanostars-1 and Au nanostars-2,which have different spire lengths and optical properties,and also spherical AuNPs.Compared to nanospheres,gold nanostars were less toxic to a variety of cells,including macrophages.Au nanostars-1 and Au nanostars-2 also manifested a similar pattern of tissue distribution upon in vivo administration in mice to that of nanospheres,and but reveled less liver retention than nanospheres.Due to their strong absorption in the near-infrared(NIR),Au nanostars-2 induced a strong hyperthermia effect in vitro upon excitation at 808 nm,and elicited a robust photothermal therapy(PTT) efficacy in ablating tumors in a mouse model of orthotopic breast cancer using 4T1 breast cancer cells.Meanwhile,Au nanostars-1 showed a great capability to enhance the Raman signal through surface-enhanced Raman spectroscopy(SERS) in 4T1 cells.Our combined results opened a new avenue to develop Au nanostars for cancer imaging and therapy.展开更多
Regulating orientation growth plays a dominant role in enhancing dielectric properties for the electromagnetic(EM)functional materials,which faces a huge challenge in the synthesis method.By sprayannealing strategy,hi...Regulating orientation growth plays a dominant role in enhancing dielectric properties for the electromagnetic(EM)functional materials,which faces a huge challenge in the synthesis method.By sprayannealing strategy,hierarchical ZnO microspheres assembled by ZnO nanorods and nanoparticles were successfully fabricated.With confined microsphere space and controlling crystal growth,oriented ZnO nanorods possess rich defects,Zn-polar,O-polar faces,and high permittivity.Meanwhile,temperaturedependency of exposed polarization surfaces is discovered in the semiconductor ZnO nanoparticles with evolved aspect ratios.As pure dielectric EM wave absorption material,the hierarchical ZnO microsphere exhibits adjustable complex permittivity and polarization behaviors.When the thickness is 2.4 mm,the hierarchical ZnO-1 absorber shows the widest efficient absorption(RL≤–10 d B)region from 9.9 to18.0 GHz(8.1 GHz,^50.6%testing frequency).The minimum reflection loss(RL)of ZnO-1 can reach–31.5 d B at only 2.0 mm.Because of the outstanding dielectric loss ability and wide absorption frequency,large-scale hierarchical ZnO microspheres can be a potential EM absorption candidate.展开更多
Faster response benefits the high-performance of magnetic material in various live applications.Hence,enhancing response speed toward the applied field via engineering advantages in structures is highly desired.In thi...Faster response benefits the high-performance of magnetic material in various live applications.Hence,enhancing response speed toward the applied field via engineering advantages in structures is highly desired.In this paper,the precise synthesis of Co nanochain with the tunable length-diameter ratio is realized via a magnetic-field-guided assembly approach.The Co nanochain exhibits enhanced microwave absorption performance(near to-60 dB,layer thickness 2.2 mm)and broader effective absorption bandwidth(over 2/3 of total S,C,X,Ku bands).Furthermore,the simulated dynamic magnetic response reveals that the domain motion in 1D chain is faster than that in 0D nanoparticle,which is the determining factor of magnetic loss upgrade.Meanwhile,based on the controllable magnetic field experiment via in situ transmission electron microscopy,the association between magnetic response and microstructure is first present at the nanometer-level.The real and imaginary parts of relative complex permeability are determined by the domain migration confined inside Co nanochain and the magnetic flux field surrounded outside Co nanochain,respectively.Importantly,these findings can be extended to the novel design of microwave absorbers and promising candidates of magnetic carriers based on 1D structure.展开更多
With the increasing complexity of electrical vehicles(EVs),the wide-speed-range high-efficiency characteristics of EV drive motors are in strict demand.In this study,the variable magnetic flux effect is introduced int...With the increasing complexity of electrical vehicles(EVs),the wide-speed-range high-efficiency characteristics of EV drive motors are in strict demand.In this study,the variable magnetic flux effect is introduced into a permanent magnet(PM)motor,and a variable magnetic flux permanent magnetic(VMF-PM)motor is proposed.First,the flux is adjusted flexibly to synchronously broaden the speed regulation range and high-efficiency region.Subsequently,an efficiency analytical model is developed considering the motor speed,current,and flux variations.It is indicated that by the purposeful design of the variable flux leakage topology,the efficiency under high speed can be improved based on a theoretical investigation of the high-efficiency boundary.In addition,based on finite element analysis,the performances before and after optimization of the key parameters of the VMF-PM motor are investigated,including the flux variable characteristics and efficiency characteristics.Finally,a prototype motor is built and tested.Both theoretical analysis and experimental results confirm that based on the assistance of the variable magnetic flux effect,the motor high-efficiency region is broadened effectively,providing a potential research path for designing a wide-speed-range high-efficiency motor.展开更多
基金The authors acknowledge financial support from the National Natural Science Foundation of China(Grant Nos.62001460,31971368,12202461,and 22104148)the Guangdong Regional Joint Funds for Young Scientists(Grant Nos.2020A1515110201 and 2020A1515110368)+2 种基金Guangdong Provincial General Funding(Grant No.2021A1515220156)Guangdong Basic and Applied Basic Research Funding-Regional Joint Fund(Grant No.2020B1515120040)Shenzhen Science and Technology Research Funding(Grant Nos.JSGG20201103153801005,JSGG20191115141601721,ZDSYS20220527171406014,JCYJ20220818101412027,JCYJ20200109115635440,and JCYJ 20200109115408041).
文摘Sensitive detection and precise quantitation of trace-level crucial biomarkers in a complex sample matrix has become an important area of research.For example,the detection of high-sensitivity cardiac troponin I (hs-cTnI) is strongly recommended in clinical guidelines for early diagnosis of acute myocardial infarction.Based on the use of an electrode modified by single-walled carbon nanotubes (SWCNTs) and a Ru(bpy)32+-doped silica nanoparticle (Ru@SiO2)/tripropylamine (TPA) system,a novel type of electrochemiluminescent (ECL) magnetoimmunosensor is developed for ultrasensitive detection of hs-cTnI.In this approach,a large amount of[Ru(bpy)3]2+is loaded in SiO2(silica nanoparticles) as luminophores with high luminescent efficiency and SWCNTs as electrode surface modification material with excellent electrooxidation ability for TPA.Subsequently,a hierarchical micropillar array of microstructures is fabricated with a magnet placed at each end to efficiently confine a single layer of immunomagnetic microbeads on the surface of the electrode and enable 7.5-fold signal enhancement In particular,the use of transparent SWCNTs to modify a transparent ITO electrode provides a two-order-of-magnitude ECL signal amplification.A good linear calibration curve is developed for hs-cTnI concentrations over a wide range from 10 fg/ml to 10 ng/ml,with the limit of detection calculated as 8.720 fg/ml (S/N=3).This ultrasensitive immunosensor exhibits superior detection performance with remarkable stability,reproducibility,and selectivity.Satisfactory recoveries are obtained in the detection of hs-cTnI in human serum,providing a potentia analysis protocol for clinical applications.
基金supported by the National Key Research and Development Program of China(2017YFC1309800)the“Outstanding University Driven by Talents”Program and Academic Promotion Program of Shandong First Medical University(2019LJ007)the Key Research and Development Program of Shandong Province(2017CXGC1214).
文摘The aim of this study was to explore the associations of moderate-to-vigorous-intensity physical activity(MVPA)time and sedentary(SED)time with a history of cardiovascular disease(CVD)and multifactorial(i.e.,blood pressure(BP),body mass index(BMI),low-density lipoprotein cholesterol(LDL-C),and glycated hemoglobin A1c(HbA1c))control status among type 2 diabetes mellitus(T2DM)patients in China.A cross-sectional analysis of 9152 people with type 2 diabetes from the Multifactorial Intervention on Type 2 Diabetes(MIDiab)study was performed.Patients were grouped according to their self-reported MVPA time(low,<150 min·week−1;moderate,150 to<450 min·week−1;high,≥450 min·week−1)and SED time(low,<4 h·d–1;moderate,4 to<8 h·d–1;high,≥8 h·d–1).Participants who self-reported a history of CVD were identified as having a CVD risk.Odds ratios(ORs)and 95%confidence intervals(CIs)of CVD risk and multifactorial control status associated with MVPA time and SED time were estimated using mixed-effect logistic regression models,adjusting for China’s geographical region characteristics.The participants had a mean±standard deviation(SD)age of(60.87±8.44)years,44.5%were women,and 25.1%had CVD.After adjustment for potential confounding factors,an inverse association between high MVPA time and CVD risk that was independent of SED time was found,whereas this association was not observed in the moderate-MVPA group.A higher MVPA time was more likely to have a positive effect on the control of BMI.Compared with the reference group(i.e.,those with MVPA time≥450 min·week−1 and SED time<4 h·d–1),CVD risk was higher in the low-MVPA group:The OR associated with an SED time<4 h·d–1 was 1.270(95%CI,1.040–1.553)and that associated with an SED time≥8 h·d–1 was 1.499(95%CI,1.149–1.955).We found that a high MVPA time(i.e.,≥450 min·week−1)was associated with lower odds of CVD risk regardless of SED time among patients with T2DM.
基金supported by the Ministry of Science and Technology of China (973 Project No. 2018YFA0209102)the National Natural Science Foundation of China (11727807, 51725101, 51672050, 61790581)Science and Technology Commission of Shanghai Municipality (16DZ2260600)。
文摘Intrinsic electric-magnetic property and special nano-micro architecture of functional materials have a significant effect on its electromagnetic wave energy conversion,especially in the microwave absorption(MA) field.Herein,porous Ni1-xCox@Carbon composites derived from metal-organic framework(MOF)were successfully synthesized via solvothermal reaction and subsequent annealing treatments.Benefiting from the coordination,carbonized bimetallic Ni-Co-MOF maintained its initial skeleton and transformed into magnetic-carbon composites with tunable nano-micro structure.During the thermal decomposition,generated magnetic particles/clusters acted as a catalyst to promote the carbon sp^2 arrangement,forming special core-shell architecture.Therefore,pure Ni@C microspheres displayed strong MA behaviors than other Ni1-xCox@Carbon composites.Surprisingly,magnetic-dielectric Ni@C composites possessed the strongest reflection loss value-59.5 dB and the effective absorption frequency covered as wide as 4.7 GHz.Meanwhile,the MA capacity also can be boosted by adjusting the absorber content from 25% to 40%.Magnetic-dielectric synergy effect of MOF-derived Ni1-xCox@Carbon microspheres was confirmed by the off-axis electron holography technology making a thorough inquiry in the MA mechanism.
基金supported by the National Natural Science Foundation of China under Grant No.11975305the West Light Foundation of The Chinese Academy of Sciences,Grant No.2017-XBQNXZ-B-008。
文摘Different switching frequencies are required when SiC metal-oxide-semiconductor field-effect transistors(MOSFETs)are switching in a space environment.In this study,the total ionizing dose(TID)responses of SiC power MOSFETs are investigated under different switching frequencies from 1 kHz to 10 MHz.A significant shift was observed in the threshold voltage as the frequency increased,which resulted in premature failure of the drain-source breakdown voltage and drain-source leakage current.The degradation is attributed to the high activation and low recovery rates of traps at high frequencies.The results of this study suggest that a targeted TID irradiation test evaluation method can be developed according to the actual switching frequency of SiC power MOSFETs.
基金This work was supported,in part,by the National Nature Science Foundation of China under grant numbers 61502240,61502096,61304205,61773219in part,by the Natural Science Foundation of Jiangsu Province under grant number BK20191401+1 种基金in part,by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)fundin part,by the Collaborative Innovation Center of Atmospheric Environment and Equipment Technology(CICAEET)fund.
文摘In order to solve the problem of high computing cost and low simulation accuracy caused by discontinuity of incision in traditional meshless model,this paper proposes a soft tissue deformation model based on the Marquardt algorithm and enrichment function.The model is based on the element-free Galerkin method,in which Kelvin viscoelastic model and adjustment function are integrated.Marquardt algorithm is applied to fit the relation between force and displacement caused by surface deformation,and the enrichment function is applied to deal with the discontinuity in the meshless method.To verify the validity of the model,the Sensable Phantom Omni force tactile interactive device is used to simulate the deformations of stomach and heart.Experimental results show that the proposed model improves the real-time performance and accuracy of soft tissue deformation simulation,which provides a new perspective for the application of the meshless method in virtual surgery.
基金Shenzhen-Hong Kong-Macao Technology Research Programme(Type C,202011033000145)Shenzhen Excellent Science and Technology Innovation Talent Training Project-Outstanding Youth Project(RCJC20200714114435061)Functional Materials Interfaces Genome(FIG)project.
文摘Technological advancements in recent decades have greatly transformed the field of material chemistry.Juxtaposing the accentuating energy demand with the pollution associated,urgent measures are required to ensure energy maximization,while reducing the extended experimental time cycle involved in energy production.In lieu of this,the prominence of catalysts in chemical reactions,particularly energy related reactions cannot be undermined,and thus it is critical to discover and design catalyst,towards the optimization of chemical processes and generation of sustainable energy.Most recently,artificial intelligence(AI)has been incorporated into several fields,particularly in advancing catalytic processes.The integration of intensive data set,machine learning models and robotics,provides a very powerful tool in modifying material synthesis and optimization by generating multifarious dataset amenable with machine learning techniques.The employment of robots automates the process of dataset and machine learning models integration in screening intermetallic surfaces of catalyst,with extreme accuracy and swiftness comparable to a number of human researchers.Although,the utilization of robots in catalyst discovery is still in its infancy,in this review we summarize current sway of artificial intelligence in catalyst discovery,briefly describe the application of databases,machine learning models and robots in this field,with emphasis on the consolidation of these monomeric units into a tripartite flow process.We point out current trends of machine learning and hybrid models of first principle calculations(DFT)for generating dataset,which is integrable into autonomous flow process of catalyst discovery.Also,we discuss catalyst discovery for renewable energy related reactions using this tripartite flow process with predetermined descriptors.
文摘Nanomaterials with strong near-infrared absorption and high photothermal conversion ability have shown great application potential in many areas including cancer treatment.However,the current photothermal conversion nanomaterials generally have poor biodegradability and would stay in
基金supported by the Talent Research Project of Hebei Province(No.HBQZYCXY010)the National Natural Science Foundation of China-Shandong Joint Fund Program entitled“Control Mechanisms of Faults on Deep Gold Deposits in Jiaodong Peninsula”(No.U2006201)+1 种基金Isotopic analyses at the University of Alberta were supported by an NSERC discovery grant to D.G.Pearsonsupported by the National Natural Science Foundation of China(No.42103024)China Postdoctoral Science Foundation(Nos.2020T130618 and 2020M682516).
文摘The Mesozoic intrusions of the Jiaodong Peninsula,eastern China,host giant gold deposits.Understanding the genesis of these deposits requires the determination of the source of the parental auriferous fluid and the timing of gold mineralization,which are strongly influenced by the cooling/uplift histories of the hosting intrusions.We performed an integrated U-Pb geochronology study on both zircon and apatite from four major magmatic episodes of the Jiaodong Peninsula.The zircon and apatite U-Pb ages are 156.9±1.2 and 137.2±2.4 Ma for the Linglong intrusion,129.9±1.0 and 125.0±3.8 Ma for the Qujia intrusion,119.5±0.7 and 117.2±1.8 Ma for the Liulinzhuang intrusion,118.6±1.0 and 111.6±1.6 Ma for the Nansu intrusion,respectively.The coupled zircon and apatite data of these granitoids indicate a slow cooling rate(11.9°C/Ma)in the Late Jurassic,and rapid uplift and cooling(35.8-29.2°C/Ma)in the Early Cretaceous.The dramatically increased uplift and cooling period in the Early Cretaceous are contemporaneous with large-scale gold mineralization in the Jiaodong Peninsula.This implies that thermal upwelling of asthenosphere and related tectonic extension played an important role in gold remobilization and precipitation.
基金supported by the grants from the National Natural Science Foundation of China(Nos.82088102,91857205,82022011,81970728,and 81930021)the Shanghai Rising-Star Program(No.21QA1408100)+2 种基金Shanghai Outstanding Academic Leaders Plan(No.20XD1422800)the National Top Young Scholar Program(Yu Xu),the Innovative Research Team of High-Level Local Universities in Shanghai,the Shanghai Clinical Research Center for Metabolic Diseases(No.19MC1910100)the Shanghai Shen Kang Hospital Development Center(Nos.SHDC2020CR1001A and SHDC2020CR3064B).
文摘Studies have found a U-shaped relationship between sleep duration and chronic kidney disease(CKD)risk,but limited research evaluated the association of reallocating excessive sleep to other behavior with CKD.We included 104538 participants from the nationwide cohort of the Risk Evaluation of Cancers in Chinese Diabetic Individuals:A Longitudinal Study,with self-reported time of daily-life behavior.Using isotemporal substitution models,we found that substituting 1 h of sleeping with sitting,walking,or moderate-to-vigorous physical activity was associated with a lower CKD prevalence.Leisure-time physical activity displacement was associated with a greater prevalence reduction than occupational physical activity in working population.In stratified analysis,a lower CKD prevalence related to substitution toward physical activity was found in long sleepers.More pronounced correlations were observed in long sleepers with diabetes than in those with prediabetes,and they benefited from other behavior substitutions toward a more active way.The U-shaped association between sleep duration and CKD prevalence implied the potential effects of insufficient and excessive sleep on the kidneys,in which the pernicious link with oversleep could be reversed by time reallocation to physical activity.The divergence in the predicted effect on CKD following time reallocation to behavior of different domains and intensities and in subpopulations with diverse metabolic statuses underlined the importance of optimizing sleeping patterns and adjusting integral behavioral composition.
基金The authors thank the Natural Science Foundation of China(Nos.10534030,10904119)the National Program on Key Science Research(No.2006CB921500)and the China Postdoctoral Science Foundation(No.20090451076)for support.
文摘A novel strategy is proposed to directly synthesize water-soluble hexagonal NaYF4 nanorods by doping rare-earth ions with large ionic radius (such as La^(3+), Ce^(3+), Pr^(3+), Nd^(3+), Sm^(3+), Eu^(3+), and Gd^(3+)), and the dopant- controlled growth mechanism is studied. Based on the doping effect, we fabricated water-soluble hexagonal NaYF4:(Yb,Er)/La and NaYF4:(Yb,Er)/Ce nanorods, which exhibited much brighter upconversion fluorescence than the corresponding cubic forms. The sizes of the nanorods can be adjusted over a broad range by changing the dopant concentration and reaction time. Furthermore, we successfully demonstrated a novel depth-sensitive multicolor bioimaging for in vivo use by employing the as-synthesized NaYF4:(Yb,Er)/La nanorods as probes.
基金the Chinese National and Provincial Major Project for New Drug Innovation(National:2008ZX09101-002,2013ZX09401301Provincial:2011A080501010)Shenzhen Municipal Major Project(2010-1746)。
文摘Chiglitazar(Carfloglitazar)is a novel peroxisome proliferator-activated receptor(PPAR)pan-agonist that has shown promising effects on glycemic control and lipid regulation in patients with type 2 diabetes.In this randomized phase 3 trial,we compared the efficacy and safety of chiglitazar with sitagliptin in patients with type 2 diabetes who had insufficient glycemic control despite a strict diet and exercise regimen.Eligible patients were randomized(1:1:1)to receive chiglitazar 32 mg(n=245),chiglitazar 48 mg(n=246),or sitagliptin 100 mg(n=248)once daily for 24 weeks.The primary endpoint was the change in glycosylated hemoglobin A_(1C)(HbA_(1c))from baseline at week 24 with the non-inferiority of chiglitazar over sitagliptin.Both chiglitazar and sitagliptin significantly reduced HbA1c at week 24 with values of-1.40%,-1.47%,and-1.39%for chiglitazar 32 mg,chiglitazar 48 mg,and sitagliptin 100 mg,respectively.Chiglitazar 32 and 48 mg were both non-inferior to sitagliptin 100 mg,with mean differences of-0.04%(95%confidential interval(Cl)-0.22 to 0.15)and-0.08%(95%Cl-0.27 to 0.10),respectively.Compared with sitagliptin,greater reduction in fasting and 2-h postprandial plasma glucose and fasting insulin was observed with chiglitazar.Overall adverse event rates were similar between the groups.A small increase in mild edema in the chiglitazar 48 mg group and slight weight gain in both chiglitazar groups were reported.The overall results demonstrated that chiglitazar possesses good efficacy and safety profile in patients with type 2 diabetes inadequately controlled with lifestyle interventions,thereby providing adequate supporting evidence for using this PPAR pan-agonist as a treatment option for type 2 diabetes.
基金This work was supported by the Ministry of Science and Technology of China(No.2018YFA0209102)the National Natural Science Foundation of China(Nos.11727807,51725101,51672050 and 61790581)the Science and Technology Commission of Shanghai Municipality(No.l6DZ2260600).
文摘Carbon-sulfur composites have draw n in creasing interest in various fields including electrocatalysis because of their unique structures.However,carb on-sulfur composite with tiny sulfur nano crystals has still received little attention.Herein,hollow porous carb on sphere-sulfur composite(HPCS-S)which possesses excellent electrochemical performance towards H2O2 has been prepared for the first time via a simple silica template method.The 2-5 nm sulfur nan ocrystals being restricted in the cha nnel of the hollow porous carb on spheres are un der a strong compressive stress,which was further con firmed by high-resoluti on tran smissi on electr on microscopy(HRTEM)and GPA.The HPCS-S nano crystals show better con ductivity tha n amorphous sulfur clusters because of the reducti on of the steric hindrance which efficie ntly promotes the electron transportation.Consequently,the higher activity and selectivity towards the 2e^oxygen reduction reaction(ORR)to H2O2 in alkaline solution was obtained.The H2O2 selectivity rises from 20%to over 70%after the sulfur addition and the H2O2 production rate achieves 183.99 mmol-gcataiyst-1 with the Faradaic efficiency of 70%.Furthermore,performance enhancement mechanism was also investigated using the den sity functional theory(DFT)calculatio ns.After the in troduci ng of sulfur nano crystals,the appeara nee of S-S bond greatly decreases the overpotential compared with S-doping,which results in significant enhancement of the electrocatalytic property.Consequently,the HPCS-S can be an efficient H2O2 production electrocatalyst in alkaline solution.
基金The authors thank Dr. Zhonghua Hao for technique help. The authors acknowledge financial support from the National Basic Research Program of China (No. 2011CB922201), the National Natural Science Foundation of China (Nos. 51372175 and 11374236), and the Fundamental Research Funds for the Central Universities (No. 2014202020203).
文摘The nanoscale core/shell heterostructure is a particularly efficient motif to combine the promising properties of plasmonic materials and rare-earth compounds; however, there remain significant challenges in the synthetic control due to the large interfacial energy between these two intrinsically unmatched materials. Herein, we report a synthetic route to grow rare-earth-vanadate shells on gold nanorod (AuNR) cores. After modifying the AuNR surface with oleate through a surfactant exchange, well-packaged rare-earth oxide (e.g., Gd2O3:Eu) shells are grown on AuNRs as a result of the multiple roles of oleate. Furthermore, the composition of the shell has been altered from oxide to vanadate (GdVO4:Eu) using an anion exchange method. Owing to the carefully designed strategy, the AuNR cores maintain the morphology during the synthesis process; thus, the final Au/GdVO4: Eu core/shell NRs exhibit strong absorption bands and high photothermal efficiency. In addition, the Au/GdVO4:Eu NRs exhibit bright Eu^3+ fluorescence with quantum yield as high as -17%; bright Sm^3+ and Dy^3+ fluorescence can also be obtained by changing the lanthanide doping in the oxide formation. Owing to the attractive integration of the plasmonic and fluorescence properties, such core/shell heterostructures will find particular applications in a wide array of areas, from biomedicine to energy.
基金This work was supported by the Ministry of Science and Technology of China(973 Project)(No.2018YFA0209102)the National Natural Science Foundation of China(Nos.11727807,51725101,51672050,and 61790581)。
文摘Design and fabrication of cost-effective transition metal and their oxides-based nanocomposites are of paramount significance for metal-air batteries and water-splitting.However,the traditional optimized designs for nanostructure are complicated,low-efficient and underperform for wide-scale applications.Herein,a novel hierarchical framework of hollow Ni/NiFe2O4-CNTs compositemicrosphere forcibly-assembled by zero-dimensional(OD)Ni/NiFo204 nanoparticle(<16 nm)and one-dimensional(1D)self-supporting CNTs was fabricated successfully.Benefitted from the unique nanostructure,such monohybrids can achieve remarkable oxygen evolution reaction(OER)performance in alkaline media with a low overpotential and superior durability,which exceeds most of the commercial catalysts based on IrO/RuO2 or other non-noble metal nanomaterials.The enhanced OER performance of Ni/NiFe2OA-CNTs composite is mainly ascribed to the increased catalytic activity and the optimized conductivity induced by the effects of strong hierarchical coupling and charge transfers between CNTs and Ni/NiFe204 nanoparticles.These effects are greatly boosted by the polarized heterojunction interfaces confirmed by electron holography.The density functional theory(DFT)calculation indicates the epitaxial Ni further enriches the intrinsic electrons contents of NiFe204 and thus accelerates absorption/desorption kinetics of OER intermediates.This work hereby paves a facile route to construct the hollow composite microsphere with excellent OER electrocatalytic activity based on non-noble metal oxide/CNTs.
基金supported by the National Key R&D Program of China(2017YFA0701303,2017YFC0111202)the National Natural Science Foundation of China(52022102,52003287)+3 种基金the Youth Innovation Promotion Association of CAS(2019353)the CAS Key Laboratory of Health Informatics,Shenzhen Institutes of Advanced Technology,Chinese Academy of Sciences(2011DP173015)the Foundation of Hunan Educational Committee(18K030)the Shenzhen Science and Technology Innovation Committee(JCYJ20180507182051636,KQJSCX20180330170232019).
文摘Shape-morphing hydrogels can be widely used to develop artificial muscles,reconfigurable biodevices,and soft robotics.However,conventional approaches for developing shape-morphing hydrogels highly rely on composite materials or complex manufacturing techniques,which limit their practical applications.Herein,we develop an unprecedented strategy to edit the shape morphing of monocomponent natural polysaccharide hydrogel films via integrating gradient cross-linking density and geometry effect.Owing to the synergistic effect,the shape morphing of chitosan(CS)hydrogel films with gradient cross-linking density can be facilely edited by changing their geometries(length-to-width ratios or thicknesses).Therefore,helix,short-side rolling,and longside rolling can be easily customized.Furthermore,various complex artificial 3D deformations such as artificial claw,horn,and flower can also be obtained by combining various flat CS hydrogel films with different geometries into one system,which can further demonstrate various shape transformations as triggered by pH.This work offers a simple strategy to construct a monocomponent hydrogel with geometry-directing programmable deformations,which provides universal insights into the design of shape-morphing polymers and will promote their applications in biodevices and soft robotics.
基金supported by the National Basic Research Program(2014CB932000)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB14000000)the National Natural Science Foundation of China(21425731,21637004)
文摘Gold nanoparticles(AuNPs) have been attractive for nanomedicine because of their pronounced optical properties.Here,we customerized the methods to synthesize two types of gold nanostars,Au nanostars-1 and Au nanostars-2,which have different spire lengths and optical properties,and also spherical AuNPs.Compared to nanospheres,gold nanostars were less toxic to a variety of cells,including macrophages.Au nanostars-1 and Au nanostars-2 also manifested a similar pattern of tissue distribution upon in vivo administration in mice to that of nanospheres,and but reveled less liver retention than nanospheres.Due to their strong absorption in the near-infrared(NIR),Au nanostars-2 induced a strong hyperthermia effect in vitro upon excitation at 808 nm,and elicited a robust photothermal therapy(PTT) efficacy in ablating tumors in a mouse model of orthotopic breast cancer using 4T1 breast cancer cells.Meanwhile,Au nanostars-1 showed a great capability to enhance the Raman signal through surface-enhanced Raman spectroscopy(SERS) in 4T1 cells.Our combined results opened a new avenue to develop Au nanostars for cancer imaging and therapy.
基金financially supported by the National Natural Science Foundation of China(Nos.51725101,11727807,51672050,61790581,22088101)the Ministry of Science and Technology of China(No.2018YFA0209102)the Infrastructure and Facility Construction Project of Zhejiang Laboratory。
文摘Regulating orientation growth plays a dominant role in enhancing dielectric properties for the electromagnetic(EM)functional materials,which faces a huge challenge in the synthesis method.By sprayannealing strategy,hierarchical ZnO microspheres assembled by ZnO nanorods and nanoparticles were successfully fabricated.With confined microsphere space and controlling crystal growth,oriented ZnO nanorods possess rich defects,Zn-polar,O-polar faces,and high permittivity.Meanwhile,temperaturedependency of exposed polarization surfaces is discovered in the semiconductor ZnO nanoparticles with evolved aspect ratios.As pure dielectric EM wave absorption material,the hierarchical ZnO microsphere exhibits adjustable complex permittivity and polarization behaviors.When the thickness is 2.4 mm,the hierarchical ZnO-1 absorber shows the widest efficient absorption(RL≤–10 d B)region from 9.9 to18.0 GHz(8.1 GHz,^50.6%testing frequency).The minimum reflection loss(RL)of ZnO-1 can reach–31.5 d B at only 2.0 mm.Because of the outstanding dielectric loss ability and wide absorption frequency,large-scale hierarchical ZnO microspheres can be a potential EM absorption candidate.
基金supported by the Ministry of Science and Technology of China(973 Project)(No.2018YFA0209102)the National Natural Science Foundation of China(Nos.11727807,51725101,51672050,and 61790581).
文摘Faster response benefits the high-performance of magnetic material in various live applications.Hence,enhancing response speed toward the applied field via engineering advantages in structures is highly desired.In this paper,the precise synthesis of Co nanochain with the tunable length-diameter ratio is realized via a magnetic-field-guided assembly approach.The Co nanochain exhibits enhanced microwave absorption performance(near to-60 dB,layer thickness 2.2 mm)and broader effective absorption bandwidth(over 2/3 of total S,C,X,Ku bands).Furthermore,the simulated dynamic magnetic response reveals that the domain motion in 1D chain is faster than that in 0D nanoparticle,which is the determining factor of magnetic loss upgrade.Meanwhile,based on the controllable magnetic field experiment via in situ transmission electron microscopy,the association between magnetic response and microstructure is first present at the nanometer-level.The real and imaginary parts of relative complex permeability are determined by the domain migration confined inside Co nanochain and the magnetic flux field surrounded outside Co nanochain,respectively.Importantly,these findings can be extended to the novel design of microwave absorbers and promising candidates of magnetic carriers based on 1D structure.
基金Supported by the Mordern Agriculture Major Core Technology Innovation Project of Jiangsu Province(CX(22)1005)by the Natural Science Foundation of Jiangsu Province for Youth(BK20220541).
文摘With the increasing complexity of electrical vehicles(EVs),the wide-speed-range high-efficiency characteristics of EV drive motors are in strict demand.In this study,the variable magnetic flux effect is introduced into a permanent magnet(PM)motor,and a variable magnetic flux permanent magnetic(VMF-PM)motor is proposed.First,the flux is adjusted flexibly to synchronously broaden the speed regulation range and high-efficiency region.Subsequently,an efficiency analytical model is developed considering the motor speed,current,and flux variations.It is indicated that by the purposeful design of the variable flux leakage topology,the efficiency under high speed can be improved based on a theoretical investigation of the high-efficiency boundary.In addition,based on finite element analysis,the performances before and after optimization of the key parameters of the VMF-PM motor are investigated,including the flux variable characteristics and efficiency characteristics.Finally,a prototype motor is built and tested.Both theoretical analysis and experimental results confirm that based on the assistance of the variable magnetic flux effect,the motor high-efficiency region is broadened effectively,providing a potential research path for designing a wide-speed-range high-efficiency motor.