The Sn−2Al filler metal was utilized to bond W90 tungsten heavy alloys by the ultrasonic-assisted coating technology in atmospheric environment at 250℃.The effects of ultrasonic power and ultrasonic time on microstru...The Sn−2Al filler metal was utilized to bond W90 tungsten heavy alloys by the ultrasonic-assisted coating technology in atmospheric environment at 250℃.The effects of ultrasonic power and ultrasonic time on microstructure and interfacial strength of Sn−2Al/W90 interface were investigated.The ultrasound improved the wettability of Sn−2Al filler metal on W90 surface.As the ultrasonic power increased and ultrasonic time increased,the size of Al phase in seam decreased.The maximum value of Sn−2Al/W90 interfacial strength reached 30.1 MPa.Based on the acoustic pressure simulation and bubble dynamics,the intensity of cavitation effect was proportional to ultrasonic power.The generated high temperature and high pressure by cavitation effect reached 83799.6 K and 1.26×10^(14) Pa,respectively.展开更多
Different from the current measurement methods for Young’s modulus of metal materials,the Young’s modulus of intermetallic compounds(IMCs)was obtained by a non-destructive method based on Brillouin light scattering(...Different from the current measurement methods for Young’s modulus of metal materials,the Young’s modulus of intermetallic compounds(IMCs)was obtained by a non-destructive method based on Brillouin light scattering(BLS)in this paper.The single-phase regions of CoSn,CoSn_(2),Cu_(3)Sn and Cu_(6)Sn_(5) phases required for BLS test were obtained by applying long-term thermal stabilization through adjusting temperature gradient.The volume fractions of the corresponding phases near the solid-liquid interfaces of the samples were 98.3%,94.2%,99.6% and 95.9%,respectively.All the independent elastic coefficients and Young’s moduli of IMCs were obtained by Brillouin scatterometer.The Young’s moduli of CoSn,CoSn_(2) and Cu_(3)Sn and Cu_(6)Sn_(5) phases obtained through the present method are 115.0,101.7,129.9 and 125.6 GPa,respectively,which are in a good agreement with the previous experimental results.Thus,the effectiveness of BLS in measuring the Young’s moduli of IMCs in bulk alloys is confirmed.展开更多
The melting and solidification process of DZ411 superalloy at different cooling rates(50,200,500°C/min)was observed in situ by high-temperature confocal laser scanning microscopy.The solidification behaviour of t...The melting and solidification process of DZ411 superalloy at different cooling rates(50,200,500°C/min)was observed in situ by high-temperature confocal laser scanning microscopy.The solidification behaviour of this alloy was also studied through other methods such as differential scanning calorimetry and scanning electron microscopy.The results show that the precipitation sequence of the main phases during the solidification of DZ411 alloy isγmatrix phase,carbide phase and Laves phase.Besides,during the solidification process of DZ411 alloy,both the dendrite thickness and dendrite spacing decreased with the increasing of cooling rate.In addition,a large amount of Ta is enriched in the dendrite stems at the end of solidification,which is the main reason for the formation of Laves phase.As the cooling rate increases,the size of the Laves phase becomes smaller and the distribution becomes more dispersed,which effectively inhibits the segregation of the alloy.展开更多
BACKGROUND Laparoscopic fenestration is a common treatment for hepatic cysts,but postoperative recurrence and complications remain concerns.AIM To evaluate suturing the liver’s round ligament to the cyst wall after l...BACKGROUND Laparoscopic fenestration is a common treatment for hepatic cysts,but postoperative recurrence and complications remain concerns.AIM To evaluate suturing the liver’s round ligament to the cyst wall after laparoscopic fenestration for hepatic cysts.METHODS This retrospective case series study involved patients who underwent the novel surgical technique at the Second People’s Hospital of Changzhou,affiliated with Nanjing Medical University,between December 2022 and March 2024.The perioperative indicators observed included operative duration,intraoperative blood loss,the occurrence of bile leakage or hemorrhage within the drainage fluid,and the duration of hospital confinement.RESULTS Fifteen patients were included.The surgeries were successfully completed laparoscopically,with a mean operative duration of 75.0±15.4 minutes and minimal intraoperative blood loss.No major complications,such as significant bleeding,bile leakage,or intra-abdominal infections,were reported.The follow-up period,ranging from 3 months to 12 months,revealed a cure rate of 40.0%and a total efficacy rate of 100%,with no cases deemed ineffective.CONCLUSION Suturing the free pedicled round ligament to the cyst wall after laparoscopic fenestration is feasible and effective,with promising cure rates.展开更多
Aqueous ammonium ion battery(AAIB)is considered as a promising candidate for next-generation energy storage device,while the limited performance of cathode material retards its further development.Seeking novel materi...Aqueous ammonium ion battery(AAIB)is considered as a promising candidate for next-generation energy storage device,while the limited performance of cathode material retards its further development.Seeking novel materials and reveal the underlying energy storage reinforcement mechanism is necessary for promoting future commercial application of AAIB.Herein,a novel electrospun Ti_(3)C_(2)T_(x)@S-V_(2)O_(5)@CNF nanofiber is constructed by sulfur doping and Ti_(3)C_(2)T_(x)introduction strategy to exert the synergetic effect on NH_(4)^(+)storage capacity.Density functional theory calculations indicate that theinduction of Ti_(3)C_(2)T_(x)can redistribute the internal charges of material,induce the downshift of the d-band center of V atoms and p-band center of S atoms to the Fermi level,thus the adsorption energy of NH_(4)^(+)is optimized.Electrochemical results show that the Ti_(3)C_(2)T_(x)@S-V_(2)O_(5)@CNF electrode displays high capacity of 576.2 mAh g^(-1)at0.5 A g^(-1),long cycle life and superior rate performance.The assembled Ti_(3)C_(2)T_(x)@S-V_(2)O_(5)@CNF//PTCDI full cell also exhibits excellent electrochemical behavior including large specific capacity of 181 mAh g^(-1)at 0.5 A g^(-1),cycling stability of 10,000 cycles at 5 A g^(-1)with no capacity decay,and good rate performance.This work gives insight into the NH_(4)^(+)storage capacity control by rational local charge regulation through S doping and heterostructure construction to facilitate electron transfer for AAIBs and other energy storage system.展开更多
Methamphetamine is one of the most prevalent drugs abused in the world.Methamphetamine abusers usually present with hyperpyrexia (39℃),hallucination and other psychiatric symptoms.However,the detailed mechanism under...Methamphetamine is one of the most prevalent drugs abused in the world.Methamphetamine abusers usually present with hyperpyrexia (39℃),hallucination and other psychiatric symptoms.However,the detailed mechanism underlying its neurotoxic action remains elusive.This study investigated the effects of methamphetamine + 39℃ on primary cortical neurons from the cortex of embryonic Sprague-Dawley rats.Primary cortex neurons were exposed to 1 mM methamphetamine + 39℃.Propidium iodide staining and lactate dehydrogenase release detection showed that methamphetamine + 39℃ triggered obvious necrosis-like death in cultured primary cortical neurons,which could be partially inhibited by receptor-interacting protein-1 (RIP1) inhibitor Necrostatin-1 partially.Western blot assay results showed that there were increases in the expressions of receptor-interacting protein-3 (RIP3) and mixed lineage kinase domain-like protein (MLKL) in the primary cortical neurons treated with 1 mM methamphetamine + 39℃ for 3 hours.After pre-treatment with RIP3 inhibitor GSK’872,propidium iodide staining and lactate dehydrogenase release detection showed that neuronal necrosis rate was significantly decreased;RIP3 and MLKL protein expression significantly decreased.Immunohistochemistry staining results also showed that the expressions of RIP3 and MLKL were up-regulated in brain specimens from humans who had died of methamphetamine abuse.Taken together,the above results suggest that methamphetamine + 39℃ can induce RIP3/MLKL regulated necroptosis,thereby resulting in neurotoxicity.The study protocol was approved by the Medical Ethics Committee of the Third Xiangya Hospital of Central South University,China (approval numbers: 2017-S026 and 2017-S033) on March 7,2017.展开更多
Pure ZnS and Ni^2+-doped ZnS nanorods (Zn1-xNixS, x=0, 0.01, 0.03, 0.05 and 0.07, mole fraction,%) were synthesized by hydrothermal method. The effects of Ni2+ doping on the phase-structure, morphology, elemental comp...Pure ZnS and Ni^2+-doped ZnS nanorods (Zn1-xNixS, x=0, 0.01, 0.03, 0.05 and 0.07, mole fraction,%) were synthesized by hydrothermal method. The effects of Ni2+ doping on the phase-structure, morphology, elemental composition and optical properties of the samples were investigated by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (EDS) and ultraviolet–visible spectroscopy (UV-Vis), respectively. The photocatalytic activity of Zn1-xNixS nanorods was evaluated by the photodegradation of organic dyes Rhodamine B (RhB) in aqueous solution under UV light irradiation. The results show that all samples exhibit wurtzite structure with good crystallization. The morphologies are one-dimensional nanorods with good dispersion, and the distortion of the lattice constant occurs. The band gap of Zn1-xNixS samples is smaller than that of pure ZnS, thus red shift occurs. Ni^2+-doped ZnS nanocrystals can enhance photocatalytic activities for the photodegradation of RhB. Especially, Zn0.97Ni0.03S sample exhibits better photocatalytic performance and photocatalytic stability for the decomposition of RhB.展开更多
Radiochromic film is a useful tool for beam quality assurance, but accurate response assessment of the film is still a problem. In this study, the response uncertainties of HDV2 film were investigated using a flatbed ...Radiochromic film is a useful tool for beam quality assurance, but accurate response assessment of the film is still a problem. In this study, the response uncertainties of HDV2 film were investigated using a flatbed scanner from both the scanning settings and interscan variability. Scanning settings are fixed conditions for scanning, including scanning resolution and focus setting.In this study, multipeak distributions of pixel values were found under some dots-per-inch values, which should be avoided, and the optimal setting of 2000 dpi without this problem was selected. By changing the focus setting, the relative standard deviation of pixel values was reduced by 36–50%. The influence of the interscan variability induced by three factors was investigated, including the outside illumination intensity, film homogeneity, and operating temperature. Scanning the film before and after irradiation at the same position was recommended. Moreover, the suitable operating temperature range for the scanner was found to be 15–24 °C, which results in stable film responses. Regarding the studied factors, correction methods and strategies were proposed, and the accurate response assessment of HDV2 film was realized. Finally, a standard operating procedure for response assessment of films was introduced. It can help other researchers study more scanners, films, and particle types.展开更多
In the process of hot-dip Zn-Al-Mg alloy coating,the plating solution dissipates heat in the direction perpendicular to the steel plate,which is considered to be a process of directional solidification.To understand t...In the process of hot-dip Zn-Al-Mg alloy coating,the plating solution dissipates heat in the direction perpendicular to the steel plate,which is considered to be a process of directional solidification.To understand the relationship between microstructure and cooling rate of Zn-Al-Mg alloys,both the phase constitution and microstructure characteristic length scales of Zn-9.5Al-3Mg-0.01Ce(wt.%)alloy were investigated by the directional solidification experiments at different growth velocities(V=40,80,160,250μm·s^(-1)).The experimental results show that the microstructure of directionally solidified Zn-9.5Al-3Mg-0.01Ce alloy is composed of primary Al dendrites and(Zn-Al-Mg2Zn11)ternary eutectics at the growth velocities ranging from 40 to 250μm·s^(-1).The primary Al dendrites are aligned regularly along the growth direction,accompanied with obvious secondary dendrites.The relationship between the microstructure length scale and the thermal parameters of solidification is obtained:λ1=374.66V-0.383,andλ2=167.5V-0.563(λ1is the primary dendrite arm spacing,andλ2 is the secondary dendrit arm spacing).In addition,through the interface response function(IRF)and the nucleation and constitutional undercooling(NCU),the phase selection of Zn-9.5Al-3Mg-0.01Ce is obtained:(Zn+Al+Mg2Zn11)ternary eutectics in the Zn-9.5Al-3Mg-0.01Ce alloy will be replaced by ternary eutectics(Zn+Al+MgZn2)when the growth rate is lower than 7.53μm·s^(-1).展开更多
Gaseous detonation propagating in a toroidal chamber was numerically studied for hydrogen/oxygen/nitrogen mixtures. The numerical method used is based on the three-dimensional Euler equations with detailed finiterate ...Gaseous detonation propagating in a toroidal chamber was numerically studied for hydrogen/oxygen/nitrogen mixtures. The numerical method used is based on the three-dimensional Euler equations with detailed finiterate chemistry. The results show that the calculated streak picture is in qualitative agreement with the picture recorded by a high speed streak camera from published literature. The three-dimensional flow field induced by a continuously rotating detonation was visualized and distinctive features of the rotating detonations were clearly depicted. Owing to the unconfined character of detonation wavelet, a deficit of detonation parameters was observed. Due to the effects of wall geometries, the strength of the outside detonation front is stronger than that of the inside portion. The detonation thus propagates with a constant circular velocity. Numerical simulation also shows three-dimensional rotating detonation structures, which display specific feature of the detonation- shock combined wave. Discrete burning gas pockets are formed due to instability of the discontinuity. It is believed that the present study could give an insight into the interest- ing properties of the continuously rotating detonation, and is thus beneficial to the design of continuous detonation propulsion systems.展开更多
The influences of cooling rate on the phase constitution,microstructural length scale,and microhardness of directionally solidified Galvalume(Zn-55Al-1.6Si)alloy were investigated by directional solidification experim...The influences of cooling rate on the phase constitution,microstructural length scale,and microhardness of directionally solidified Galvalume(Zn-55Al-1.6Si)alloy were investigated by directional solidification experiments at different withdrawal speeds(5,10,20,50,100,200,and 400μm·s^(-1)).The results show that the microstructure of directionally solidified Galvalume alloys is composed of primary Al dendrites,Si-rich phase and(Zn-Al-Si)ternary eutectics at the withdrawal speed ranging from 5 to 400μm·s^(-1).As the withdrawal speed increases,the segregation of Si element intensifies,resulting in an increase in the area fraction of the Si-rich phase.In addition,the primary Al dendrites show significant refinement with an increase in the withdrawal speed.The relationship between the primary dendrite arm spacing(λ_(1))and the thermal parameters of solidification is obtained:λ_(1)=127.3V^(-0.31).Moreover,as the withdrawal speed increases from 5 to 400μm·s^(-1),the microhardness of the alloy increases from 90 HV to 151 HV.This is a combined effect of grain refinement and second-phase strengthening.展开更多
Contact binaries consist of two strongly interacting component stars where they are filling their critical Roche lobes and sharing a common envelope.Most of them are main-sequence stars,but some of them are post main-...Contact binaries consist of two strongly interacting component stars where they are filling their critical Roche lobes and sharing a common envelope.Most of them are main-sequence stars,but some of them are post main-sequence systems.They are good astrophysical laboratories for studying several problems such as the merging of binary stars,evolution of the common envelope,the origin of luminous red nova outbursts and the formation of rapidly rotating single stars with possible planetary systems.A large number of contact binary candidates were detected by several photometric surveys around the world and many of them were observed by the LAMOST spectroscopic survey.Based on follow-up observations,the evolutionary states and geometrical structures of some systems were understood well.In this review,we will introduce and catalog new stellar atmospheric parameters(i.e.,the effective temperature(Teff),the gravitational acceleration(log(g)),metallicity([Fe/H])and radial velocity(Vr))for 9149 EW-type contact binaries that were obtained based on low-and medium-resolution spectroscopic surveys of LAMOST.Then we will focus on several groups of contact binary stars,i.e.,marginal contact binary systems,deep and low-mass ratio contact binary stars,binary systems below the short-period limit of contact binaries and evolved contact binaries.Marginal contact binaries are at the beginning of the contact stage,while deep and low-mass ratio contact binary stars are at the final evolutionary stage of tidally locked binaries.Several statistical relations including the period-temperature relation are determined well by applying LAMOST data and their formation and evolutionary states are reviewed.The period-color relation of M-type binaries reveals that there are contact binaries below the short-period limit.Searching for and investigating contact binaries near and below this limit will help us to understand the formation of contact binary systems and a new prediction for the short-period limit is about 0.15 d.Some evolved contact binaries were detected by the LAMOST survey where both components are sub-giants or giants.They provide a good opportunity to investigate evolution of the common envelope and are the progenitors of luminous red novae like V1309 Sco.展开更多
The Chinese tree shrew(Tupaia belangeri chinensis),a member of the mammalian order Scandentia,exhibits considerable similarities with primates,including humans,in aspects of its nervous,immune,and metabolic systems.Th...The Chinese tree shrew(Tupaia belangeri chinensis),a member of the mammalian order Scandentia,exhibits considerable similarities with primates,including humans,in aspects of its nervous,immune,and metabolic systems.These similarities have established the tree shrew as a promising experimental model for biomedical research on cancer,infectious diseases,metabolic disorders,and mental health conditions.Herein,we used metatranscriptomic sequencing to analyze plasma,as well as oral and anal swab samples,from 105 healthy asymptomatic tree shrews to identify the presence of potential zoonotic viruses.In total,eight mammalian viruses with complete genomes were identified,belonging to six viral families,including Flaviviridae,Hepeviridae,Parvovirinae,Picornaviridae,Sedoreoviridae,and Spinareoviridae.Notably,the presence of rotavirus was recorded in tree shrews for the first time.Three viruses-hepacivirus 1,parvovirus,and picornavirus-exhibited low genetic similarity(<70%)with previously reported viruses at the whole-genome scale,indicating novelty.Conversely,three other viruses-hepacivirus 2,hepatovirus A and hepevirus-exhibited high similarity(>94%)to known viral strains.Phylogenetic analyses also revealed that the rotavirus and mammalian orthoreovirus identified in this study may be novel reassortants.These findings provide insights into the diverse viral spectrum present in captive Chinese tree shrews,highlighting the necessity for further research into their potential for crossspecies transmission.展开更多
To study vertical sag requirements and factors affecting the stretched wire alignment method,the vertical sag equation is first derived theoretically.Subsequently,the influencing factors(such as the hanging weight or ...To study vertical sag requirements and factors affecting the stretched wire alignment method,the vertical sag equation is first derived theoretically.Subsequently,the influencing factors(such as the hanging weight or tension,span length,temperature change,elastic deformation,and the Earth’s rotation)of the vertical sag are summarized,and their validity is verified through actual measurements.Finally,the essential factors affecting vertical sag,i.e.,the specific strength and length,are discussed.It is believed that the vertical sag of a stretched wire is proportional to the square of the length and inversely proportional to the specific strength of the material.展开更多
The use of low-grade,refractory and composite paragenetic mineral resources is necessary for overcoming the shortage of iron ore resources in China.As a solution to the treatment of such iron ores,the direct reduction...The use of low-grade,refractory and composite paragenetic mineral resources is necessary for overcoming the shortage of iron ore resources in China.As a solution to the treatment of such iron ores,the direct reduction of carbon-bearing pellets can ensure complete iron removal and the effective enrichment of other high-value elements.Thus,this technology enjoys a broad application prospect.However,there are several problems with low-temperature reduction,such as low iron ore reaction efficiency,long reaction time,and high energy consumption.To improve the low-temperature carbothermic reduction efficiency of iron ores,a static magnetic field with magnetic induction intensity of 1.0 T was introduced.An isothermal reduction experiment was conducted at 1223 K to study the low-temperature self-reduction characteristics of carbon-bearing pellets of Bayan Obo lean iron ores in the static magnetic field.Also,the acting mechanism of the magnetic field was explored from the perspective of the reduction process,reaction efficiency,phase composition,microstructure changes,and dynamic behavior of iron ores.The results showed that the magnetic field can increase the low-temperature reduction rate of carbon-bearing pellets of Bayan Obo lean iron ores.Under the conditions of reduction temperature of 1223 K,magnetic induction intensity of 1.0 T,and reduction time of 60 min,the reduction degree was 92.42%,1.65 times that without a magnetic field.The magnetic field promoted the replacement of Ca^(2+)and Fe^(2+),so that the hard-to-reduce iron-bearing silicates were reduced in the order of Fe2SiO_(4)→(Ca,Na)FeSiO_(4)→FeO→Fe.The magnetic field enabled loose minerals,more pores and cracks,and changes in the growth morphology and distribution position of metallic iron.Compared with the case under the non-magnetic condition,the metallic iron precipitated from the slag phase in a foliated shape,separated from the matrix iron oxides,and grew up at the junction of the slag phase and coke.The magnetic field significantly increased the interfacial chemical reaction rate of the carbothermic reduction of iron ores and reduced the internal diffusion resistance of gas in the product layer.Specifically,the interfacial chemical reaction rate increased by 138%and the internal diffusion coefficient increased by 309%.Therefore,the effect of the magnetic field on the internal diffusion resistance was the main cause for strengthening the low-temperature reduction of iron ores.展开更多
Efficient bifunction electrocatalyst is extremely interesting for electrochemical overall water splitting(OWS).Herein,a new RuO_(2)-Ru/MoO_(2)@CC(RRM/CC)bifunctional electrocatalyst was prepared via a solid phase reac...Efficient bifunction electrocatalyst is extremely interesting for electrochemical overall water splitting(OWS).Herein,a new RuO_(2)-Ru/MoO_(2)@CC(RRM/CC)bifunctional electrocatalyst was prepared via a solid phase reaction strategy.To obtain a suitable precursor for SPR,MoS_(2)nanosheets and RuO_(2)nanoparticles(NPs)were sequentially loaded onto carbon cloth conductive substrate.Subsequently,the prepared RuO_(2)/MoS_(2)/CC precursor was sealed in a furnace and annealed in Ar to trigger the redox SPR.After SPR,active RuO_(2)-Ru/MoO_(2)units containing metal–metal oxide interfaces were formed on CC substrate uniformly.The optimized RRM/CC sample annealed at 400℃exhibited a overpotential of 13 m V for hydrogen evolution reaction(HER)and 231 mV for oxygen evolution reaction(OER)at 10 mA·cm^(-2)under alkaline condition,respectively,which can be deduced to the modulated electronic structure and unique hierarchica structure.In addition,a low cell voltage of 1.48 V for OWS was required at 10 mA·cm^(-2)under alkaline condition Meanwhile,RRM/CC exhibited excellent pH-independent durability.展开更多
We present the first photometric and orbital period investigations for a neglected totally eclipsing contact binary IP Lyn.The photometric solutions derived from both ground-based and several surveys'observations ...We present the first photometric and orbital period investigations for a neglected totally eclipsing contact binary IP Lyn.The photometric solutions derived from both ground-based and several surveys'observations suggest that it is a shallow contact binary with an extremely low mass ratio of 0.055.The weak asymmetry observed in our multiple band light curves can be interpreted as a result of an active cool spot on the primary.The absolute physical parameters were determined with the Gaia-distance-based method and checked by an empirical relation.Combining the eclipse timings collected from the literature and those derived from our and variable surveys'observations,we find that IP Lyn has been undergoing a secular orbital period increase for the past two decades,implying a mass transfer from the less massive secondary to the primary.By comparing the current parameters with the critical instability ones,we infer that IP Lyn is currently stable in spite of its relatively low mass ratio and orbital angular momentum.Finally,from a catalog of 117 extremely low mass ratio contact binaries,we find that their orbital angular momenta are significantly lower than those of the contact binaries with a relatively high mass ratio,suggesting they should be at the late evolutionary stage of a contact binary.展开更多
The effects of Ta content(2.72wt.%,3.10wt.%and 4.00wt.%)on the solidification characteristics and mechanical properties of directionally solidified DZ411 Ni-based superalloys were investigated.It is found that the con...The effects of Ta content(2.72wt.%,3.10wt.%and 4.00wt.%)on the solidification characteristics and mechanical properties of directionally solidified DZ411 Ni-based superalloys were investigated.It is found that the content of Mo decreases with the increase of Ta in liquid phase after directional solidification,indicating the addition of Ta can reduce the element segregation in alloys.The primary and secondary dendrite arm spacings(PDAS and SDAS)of the DZ411 alloy increase with the addition of Ta,which are consistent with the models by Hunt and Wagner.The increase of PDAS and SDAS can provide enough space for the growth of tertiary dendrite arms,which hinders the growth of unfavorably oriented primary dendrites.As a result,the addition of Ta facilitates the growth of favorably oriented dendrites.More MC carbides andγ-γ'eutectics are formed in the interdendritic regions,which is attributed to the segregation of Ta in the liquid phase.Furthermore,the degree of supersaturation of W,Mo inγmatrix increases with the increase of Ta,thus,the addition of Ta promotes the formation of TCP phase.The addition of Ta also increases the microhardness in both the primary dendrite and interdendritic regions of the alloy,and the microhardness of the primary dendrite is closer to that in interdendritic regions with the increase of Ta.展开更多
In recent years,transition metal silicides have become the potential high temperature materials.The ternary silicide has attracted the attention of scientists and researchers.But their inherent brittle behaviors hinde...In recent years,transition metal silicides have become the potential high temperature materials.The ternary silicide has attracted the attention of scientists and researchers.But their inherent brittle behaviors hinder their wide applications.In this work,we use the first-principles method to design four vacancy defects and discuss the effects of vacancy defects on the structural stability,mechanical properties,electronic and thermodynamic properties of hexagonal Cr;BSi;silicide.The data of lattice vibration and thermodynamic parameters indicate that the Cr;BSi;with different atomic vacancies can possess the structural stabilities.The different atomic vacancies change the mechanical properties and induce the Cr;BSi;to implement the brittle-to-ductile transition.The shear deformation resistance and volume deformation resistance of Cr;BSi;are weakened by different vacancy defects.But the brittleness behavior is remarkably improved.The structural stability and brittle-to-ductile transition of Cr;BSi;with different vacancies are explored by the electronic structures.Moreover,the thermal parameters indicate that the Cr;BSi;with vacancies exhibit different thermodynamic properties with temperature rising.展开更多
The packaging materials with cushioning performance are used to prevent the internal contents from being damaged by the impact and vibration of external forces.The polyurethane microcellular elastomers(PUMEs)can absor...The packaging materials with cushioning performance are used to prevent the internal contents from being damaged by the impact and vibration of external forces.The polyurethane microcellular elastomers(PUMEs)can absorb energy through cell collapse and molecular chain creep.In this study,PUMEs with different densities were investigated by scanning electron microscopy,dynamic mechanical analysis and dynamic compression tests.PUMEs exhibited significant im pact resistance and the maximum peak stress attenuation ratio reached 73.33%.The protective equipment was made by PUME with the optimal density of 600 kg/m^(3),and then the acceleration sensing device installed with the same protective equipment fell from a height of 3,5 and 10 m to evaluate the energy-absorbing property and reusability of PUMEs.The results showed that PUMEs equipment reduced the peak acceleration of the device by 93.84%,with a maximum deviation of 9%between actual test and simulation,and shortened the impact time of first landing by 57.39%.In addition,the equipment PUMEs equipment could effectively reduce the stress on the protected items.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52105330,52175307)the Natural Science Foundation of Shandong Province,China(No.ZR2023JQ021)。
文摘The Sn−2Al filler metal was utilized to bond W90 tungsten heavy alloys by the ultrasonic-assisted coating technology in atmospheric environment at 250℃.The effects of ultrasonic power and ultrasonic time on microstructure and interfacial strength of Sn−2Al/W90 interface were investigated.The ultrasound improved the wettability of Sn−2Al filler metal on W90 surface.As the ultrasonic power increased and ultrasonic time increased,the size of Al phase in seam decreased.The maximum value of Sn−2Al/W90 interfacial strength reached 30.1 MPa.Based on the acoustic pressure simulation and bubble dynamics,the intensity of cavitation effect was proportional to ultrasonic power.The generated high temperature and high pressure by cavitation effect reached 83799.6 K and 1.26×10^(14) Pa,respectively.
基金supported by the Gansu Key Research and Development Project,China(No.23YFGA0003)the Key Science and Technology Projects of Gansu Province,China(No.22ZD6GB019)+2 种基金Gansu Provincial Joint Research Fund,China(No.23JRRC0004)the Industry Support Plan of Gansu Universities,China(No.2024CYZC-01)the Fundamental Research Funds for the Central Universities,China(No.lzujbky-2022-ey15).
文摘Different from the current measurement methods for Young’s modulus of metal materials,the Young’s modulus of intermetallic compounds(IMCs)was obtained by a non-destructive method based on Brillouin light scattering(BLS)in this paper.The single-phase regions of CoSn,CoSn_(2),Cu_(3)Sn and Cu_(6)Sn_(5) phases required for BLS test were obtained by applying long-term thermal stabilization through adjusting temperature gradient.The volume fractions of the corresponding phases near the solid-liquid interfaces of the samples were 98.3%,94.2%,99.6% and 95.9%,respectively.All the independent elastic coefficients and Young’s moduli of IMCs were obtained by Brillouin scatterometer.The Young’s moduli of CoSn,CoSn_(2) and Cu_(3)Sn and Cu_(6)Sn_(5) phases obtained through the present method are 115.0,101.7,129.9 and 125.6 GPa,respectively,which are in a good agreement with the previous experimental results.Thus,the effectiveness of BLS in measuring the Young’s moduli of IMCs in bulk alloys is confirmed.
基金funded by the Key Science and Technology Projects of Gansu Province(Grant No.252DGA006)Central Fund for Guiding Local Science and Technology Development Projects(Grant No.25ZYJB001)+3 种基金Gansu Key Research and Development Project(Grant No.23YFGA0003)Gansu Provincial Joint Research Fund(Grant No.24JRRB004)the Industry support plan of Gansu Universities(Grant No.2024CYZC-01)the Science and Technology Projects of Jiayuguan City(No.24-10,QKJ24-01,QKJ24-10).
文摘The melting and solidification process of DZ411 superalloy at different cooling rates(50,200,500°C/min)was observed in situ by high-temperature confocal laser scanning microscopy.The solidification behaviour of this alloy was also studied through other methods such as differential scanning calorimetry and scanning electron microscopy.The results show that the precipitation sequence of the main phases during the solidification of DZ411 alloy isγmatrix phase,carbide phase and Laves phase.Besides,during the solidification process of DZ411 alloy,both the dendrite thickness and dendrite spacing decreased with the increasing of cooling rate.In addition,a large amount of Ta is enriched in the dendrite stems at the end of solidification,which is the main reason for the formation of Laves phase.As the cooling rate increases,the size of the Laves phase becomes smaller and the distribution becomes more dispersed,which effectively inhibits the segregation of the alloy.
文摘BACKGROUND Laparoscopic fenestration is a common treatment for hepatic cysts,but postoperative recurrence and complications remain concerns.AIM To evaluate suturing the liver’s round ligament to the cyst wall after laparoscopic fenestration for hepatic cysts.METHODS This retrospective case series study involved patients who underwent the novel surgical technique at the Second People’s Hospital of Changzhou,affiliated with Nanjing Medical University,between December 2022 and March 2024.The perioperative indicators observed included operative duration,intraoperative blood loss,the occurrence of bile leakage or hemorrhage within the drainage fluid,and the duration of hospital confinement.RESULTS Fifteen patients were included.The surgeries were successfully completed laparoscopically,with a mean operative duration of 75.0±15.4 minutes and minimal intraoperative blood loss.No major complications,such as significant bleeding,bile leakage,or intra-abdominal infections,were reported.The follow-up period,ranging from 3 months to 12 months,revealed a cure rate of 40.0%and a total efficacy rate of 100%,with no cases deemed ineffective.CONCLUSION Suturing the free pedicled round ligament to the cyst wall after laparoscopic fenestration is feasible and effective,with promising cure rates.
基金financially supported by the National Natural Science Foundation of China(No.52406067)Guang Dong Basic and Applied Basic Research Foundation(No.2023A1515110139)+7 种基金Shenzhen Science and Technology Program(No.JCYJ20230807153607017)the Sectorfor the National Natural Science Foundation of China(No.52105236)the Scientific Research Program Funded by Shaanxi Provincial Education Department(No.23JK0459)the Natural Science Foundation of Shaanxi Province,China(Nos.2024JC-YBQN-0162 and2024JC-YBQN-0560)Hubei Key Laboratory of Energy Storage and Power Battery(Hubei University of Automotive Technology)(No.ZDK22024B05)the Key Laboratory of Functional Textile Material and Product,Ministry of Education(No.2024FTMP017)the Open Project of Xi'an Key Laboratory of Advanced Optoelectronic Materials and Energy Conversion Devices(No.XJKFKT-2024-3)the Open Research Project supported by State Key Laboratory for Mechanical Behavior of Materials(No.202325013)
文摘Aqueous ammonium ion battery(AAIB)is considered as a promising candidate for next-generation energy storage device,while the limited performance of cathode material retards its further development.Seeking novel materials and reveal the underlying energy storage reinforcement mechanism is necessary for promoting future commercial application of AAIB.Herein,a novel electrospun Ti_(3)C_(2)T_(x)@S-V_(2)O_(5)@CNF nanofiber is constructed by sulfur doping and Ti_(3)C_(2)T_(x)introduction strategy to exert the synergetic effect on NH_(4)^(+)storage capacity.Density functional theory calculations indicate that theinduction of Ti_(3)C_(2)T_(x)can redistribute the internal charges of material,induce the downshift of the d-band center of V atoms and p-band center of S atoms to the Fermi level,thus the adsorption energy of NH_(4)^(+)is optimized.Electrochemical results show that the Ti_(3)C_(2)T_(x)@S-V_(2)O_(5)@CNF electrode displays high capacity of 576.2 mAh g^(-1)at0.5 A g^(-1),long cycle life and superior rate performance.The assembled Ti_(3)C_(2)T_(x)@S-V_(2)O_(5)@CNF//PTCDI full cell also exhibits excellent electrochemical behavior including large specific capacity of 181 mAh g^(-1)at 0.5 A g^(-1),cycling stability of 10,000 cycles at 5 A g^(-1)with no capacity decay,and good rate performance.This work gives insight into the NH_(4)^(+)storage capacity control by rational local charge regulation through S doping and heterostructure construction to facilitate electron transfer for AAIBs and other energy storage system.
基金funded by the National Natural Science Foundation of China,No.81971891(to KX),81571939(to KX),81772134(to KX),81772024(to JY),and 81860781(to FXL)the Key Research and Development Program of Hunan Province of China,No.2018SK2091(to KX)+1 种基金the Natural Science Foundation of Hunan Province of China,No.2017JJ2339(to JY)the Wu Jie-Ping Medical Foundation of the Minister of Health of China,No.320.6750.14118(to KX)
文摘Methamphetamine is one of the most prevalent drugs abused in the world.Methamphetamine abusers usually present with hyperpyrexia (39℃),hallucination and other psychiatric symptoms.However,the detailed mechanism underlying its neurotoxic action remains elusive.This study investigated the effects of methamphetamine + 39℃ on primary cortical neurons from the cortex of embryonic Sprague-Dawley rats.Primary cortex neurons were exposed to 1 mM methamphetamine + 39℃.Propidium iodide staining and lactate dehydrogenase release detection showed that methamphetamine + 39℃ triggered obvious necrosis-like death in cultured primary cortical neurons,which could be partially inhibited by receptor-interacting protein-1 (RIP1) inhibitor Necrostatin-1 partially.Western blot assay results showed that there were increases in the expressions of receptor-interacting protein-3 (RIP3) and mixed lineage kinase domain-like protein (MLKL) in the primary cortical neurons treated with 1 mM methamphetamine + 39℃ for 3 hours.After pre-treatment with RIP3 inhibitor GSK’872,propidium iodide staining and lactate dehydrogenase release detection showed that neuronal necrosis rate was significantly decreased;RIP3 and MLKL protein expression significantly decreased.Immunohistochemistry staining results also showed that the expressions of RIP3 and MLKL were up-regulated in brain specimens from humans who had died of methamphetamine abuse.Taken together,the above results suggest that methamphetamine + 39℃ can induce RIP3/MLKL regulated necroptosis,thereby resulting in neurotoxicity.The study protocol was approved by the Medical Ethics Committee of the Third Xiangya Hospital of Central South University,China (approval numbers: 2017-S026 and 2017-S033) on March 7,2017.
基金Project(51261015)supported by the National Natural Science Foundation of ChinaProject(1308RJZA238)supported by the Natural Science Foundation of Gansu Province,China
文摘Pure ZnS and Ni^2+-doped ZnS nanorods (Zn1-xNixS, x=0, 0.01, 0.03, 0.05 and 0.07, mole fraction,%) were synthesized by hydrothermal method. The effects of Ni2+ doping on the phase-structure, morphology, elemental composition and optical properties of the samples were investigated by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (EDS) and ultraviolet–visible spectroscopy (UV-Vis), respectively. The photocatalytic activity of Zn1-xNixS nanorods was evaluated by the photodegradation of organic dyes Rhodamine B (RhB) in aqueous solution under UV light irradiation. The results show that all samples exhibit wurtzite structure with good crystallization. The morphologies are one-dimensional nanorods with good dispersion, and the distortion of the lattice constant occurs. The band gap of Zn1-xNixS samples is smaller than that of pure ZnS, thus red shift occurs. Ni^2+-doped ZnS nanocrystals can enhance photocatalytic activities for the photodegradation of RhB. Especially, Zn0.97Ni0.03S sample exhibits better photocatalytic performance and photocatalytic stability for the decomposition of RhB.
基金supported by the National Natural Science Foundation of China(No.11805100)the Natural Science Foundation of Jiangsu Province(No.BK20180415)+3 种基金the National Key Research and Development Program(No.2016YFE0103600)the National Key Research and Development Program(No.2017YFC0107700)the Foundation of Graduate Innovation Center in NUAA(No.kfjj20180614)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Radiochromic film is a useful tool for beam quality assurance, but accurate response assessment of the film is still a problem. In this study, the response uncertainties of HDV2 film were investigated using a flatbed scanner from both the scanning settings and interscan variability. Scanning settings are fixed conditions for scanning, including scanning resolution and focus setting.In this study, multipeak distributions of pixel values were found under some dots-per-inch values, which should be avoided, and the optimal setting of 2000 dpi without this problem was selected. By changing the focus setting, the relative standard deviation of pixel values was reduced by 36–50%. The influence of the interscan variability induced by three factors was investigated, including the outside illumination intensity, film homogeneity, and operating temperature. Scanning the film before and after irradiation at the same position was recommended. Moreover, the suitable operating temperature range for the scanner was found to be 15–24 °C, which results in stable film responses. Regarding the studied factors, correction methods and strategies were proposed, and the accurate response assessment of HDV2 film was realized. Finally, a standard operating procedure for response assessment of films was introduced. It can help other researchers study more scanners, films, and particle types.
基金funded by the Key Science and Technology Projects of Gansu Province(Grant No.22ZD6GB019)the fund of the State Key Laboratory of Solidification Processing in NPU(Grant No.SKLSP202204)the Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2022-ey15)。
文摘In the process of hot-dip Zn-Al-Mg alloy coating,the plating solution dissipates heat in the direction perpendicular to the steel plate,which is considered to be a process of directional solidification.To understand the relationship between microstructure and cooling rate of Zn-Al-Mg alloys,both the phase constitution and microstructure characteristic length scales of Zn-9.5Al-3Mg-0.01Ce(wt.%)alloy were investigated by the directional solidification experiments at different growth velocities(V=40,80,160,250μm·s^(-1)).The experimental results show that the microstructure of directionally solidified Zn-9.5Al-3Mg-0.01Ce alloy is composed of primary Al dendrites and(Zn-Al-Mg2Zn11)ternary eutectics at the growth velocities ranging from 40 to 250μm·s^(-1).The primary Al dendrites are aligned regularly along the growth direction,accompanied with obvious secondary dendrites.The relationship between the microstructure length scale and the thermal parameters of solidification is obtained:λ1=374.66V-0.383,andλ2=167.5V-0.563(λ1is the primary dendrite arm spacing,andλ2 is the secondary dendrit arm spacing).In addition,through the interface response function(IRF)and the nucleation and constitutional undercooling(NCU),the phase selection of Zn-9.5Al-3Mg-0.01Ce is obtained:(Zn+Al+Mg2Zn11)ternary eutectics in the Zn-9.5Al-3Mg-0.01Ce alloy will be replaced by ternary eutectics(Zn+Al+MgZn2)when the growth rate is lower than 7.53μm·s^(-1).
基金supported by the National Natural Science Foundation of China (10872096)the Open Fund of State Key Laboratory of Explosion Science and Technology, Beijing University of Science and Technology (KFJJ09-13)
文摘Gaseous detonation propagating in a toroidal chamber was numerically studied for hydrogen/oxygen/nitrogen mixtures. The numerical method used is based on the three-dimensional Euler equations with detailed finiterate chemistry. The results show that the calculated streak picture is in qualitative agreement with the picture recorded by a high speed streak camera from published literature. The three-dimensional flow field induced by a continuously rotating detonation was visualized and distinctive features of the rotating detonations were clearly depicted. Owing to the unconfined character of detonation wavelet, a deficit of detonation parameters was observed. Due to the effects of wall geometries, the strength of the outside detonation front is stronger than that of the inside portion. The detonation thus propagates with a constant circular velocity. Numerical simulation also shows three-dimensional rotating detonation structures, which display specific feature of the detonation- shock combined wave. Discrete burning gas pockets are formed due to instability of the discontinuity. It is believed that the present study could give an insight into the interest- ing properties of the continuously rotating detonation, and is thus beneficial to the design of continuous detonation propulsion systems.
基金supported by the Key Science and Technology Projects of Gansu Province(Grant No.22ZD6GB019)Gansu Key Research and Development Project(Grant No.23YFGA0003)+2 种基金Gansu Provincial Joint Research Fund(Grant No.23JRRC0004)Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2022-ey15)the State Key Laboratory of Solidification Processing in NPU(Grant No.SKLSP202204).
文摘The influences of cooling rate on the phase constitution,microstructural length scale,and microhardness of directionally solidified Galvalume(Zn-55Al-1.6Si)alloy were investigated by directional solidification experiments at different withdrawal speeds(5,10,20,50,100,200,and 400μm·s^(-1)).The results show that the microstructure of directionally solidified Galvalume alloys is composed of primary Al dendrites,Si-rich phase and(Zn-Al-Si)ternary eutectics at the withdrawal speed ranging from 5 to 400μm·s^(-1).As the withdrawal speed increases,the segregation of Si element intensifies,resulting in an increase in the area fraction of the Si-rich phase.In addition,the primary Al dendrites show significant refinement with an increase in the withdrawal speed.The relationship between the primary dendrite arm spacing(λ_(1))and the thermal parameters of solidification is obtained:λ_(1)=127.3V^(-0.31).Moreover,as the withdrawal speed increases from 5 to 400μm·s^(-1),the microhardness of the alloy increases from 90 HV to 151 HV.This is a combined effect of grain refinement and second-phase strengthening.
基金supported by the National Natural Science Foundation of China(Nos.11933008,11922306,11773066 and 11903076)the Open Project Program of the Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences。
文摘Contact binaries consist of two strongly interacting component stars where they are filling their critical Roche lobes and sharing a common envelope.Most of them are main-sequence stars,but some of them are post main-sequence systems.They are good astrophysical laboratories for studying several problems such as the merging of binary stars,evolution of the common envelope,the origin of luminous red nova outbursts and the formation of rapidly rotating single stars with possible planetary systems.A large number of contact binary candidates were detected by several photometric surveys around the world and many of them were observed by the LAMOST spectroscopic survey.Based on follow-up observations,the evolutionary states and geometrical structures of some systems were understood well.In this review,we will introduce and catalog new stellar atmospheric parameters(i.e.,the effective temperature(Teff),the gravitational acceleration(log(g)),metallicity([Fe/H])and radial velocity(Vr))for 9149 EW-type contact binaries that were obtained based on low-and medium-resolution spectroscopic surveys of LAMOST.Then we will focus on several groups of contact binary stars,i.e.,marginal contact binary systems,deep and low-mass ratio contact binary stars,binary systems below the short-period limit of contact binaries and evolved contact binaries.Marginal contact binaries are at the beginning of the contact stage,while deep and low-mass ratio contact binary stars are at the final evolutionary stage of tidally locked binaries.Several statistical relations including the period-temperature relation are determined well by applying LAMOST data and their formation and evolutionary states are reviewed.The period-color relation of M-type binaries reveals that there are contact binaries below the short-period limit.Searching for and investigating contact binaries near and below this limit will help us to understand the formation of contact binary systems and a new prediction for the short-period limit is about 0.15 d.Some evolved contact binaries were detected by the LAMOST survey where both components are sub-giants or giants.They provide a good opportunity to investigate evolution of the common envelope and are the progenitors of luminous red novae like V1309 Sco.
基金supported by the National Key R&D Program of China (2021YFC2300900,2021YFC2301300)Academic Promotion Programme of Shandong First Medical University (2019QL006)+2 种基金Natural Science Foundation of Shandong Province (ZR2020QH274)Yunnan Key Research and Development Program (202103AQ100001,202102AA310055)Key Program of Chinese Academy of Sciences (KJZD-SW-L11)。
文摘The Chinese tree shrew(Tupaia belangeri chinensis),a member of the mammalian order Scandentia,exhibits considerable similarities with primates,including humans,in aspects of its nervous,immune,and metabolic systems.These similarities have established the tree shrew as a promising experimental model for biomedical research on cancer,infectious diseases,metabolic disorders,and mental health conditions.Herein,we used metatranscriptomic sequencing to analyze plasma,as well as oral and anal swab samples,from 105 healthy asymptomatic tree shrews to identify the presence of potential zoonotic viruses.In total,eight mammalian viruses with complete genomes were identified,belonging to six viral families,including Flaviviridae,Hepeviridae,Parvovirinae,Picornaviridae,Sedoreoviridae,and Spinareoviridae.Notably,the presence of rotavirus was recorded in tree shrews for the first time.Three viruses-hepacivirus 1,parvovirus,and picornavirus-exhibited low genetic similarity(<70%)with previously reported viruses at the whole-genome scale,indicating novelty.Conversely,three other viruses-hepacivirus 2,hepatovirus A and hepevirus-exhibited high similarity(>94%)to known viral strains.Phylogenetic analyses also revealed that the rotavirus and mammalian orthoreovirus identified in this study may be novel reassortants.These findings provide insights into the diverse viral spectrum present in captive Chinese tree shrews,highlighting the necessity for further research into their potential for crossspecies transmission.
基金Large Research Infrastructures“China initiative Accelerator Driven System”(No.2017-000052-75-01-000590).
文摘To study vertical sag requirements and factors affecting the stretched wire alignment method,the vertical sag equation is first derived theoretically.Subsequently,the influencing factors(such as the hanging weight or tension,span length,temperature change,elastic deformation,and the Earth’s rotation)of the vertical sag are summarized,and their validity is verified through actual measurements.Finally,the essential factors affecting vertical sag,i.e.,the specific strength and length,are discussed.It is believed that the vertical sag of a stretched wire is proportional to the square of the length and inversely proportional to the specific strength of the material.
基金The authors are grateful for the financial support from the Natural Science Foundation of Inner Mongolia(2019MS05010)the National Natural Science Foundation of China(51464039 and 52064044).
文摘The use of low-grade,refractory and composite paragenetic mineral resources is necessary for overcoming the shortage of iron ore resources in China.As a solution to the treatment of such iron ores,the direct reduction of carbon-bearing pellets can ensure complete iron removal and the effective enrichment of other high-value elements.Thus,this technology enjoys a broad application prospect.However,there are several problems with low-temperature reduction,such as low iron ore reaction efficiency,long reaction time,and high energy consumption.To improve the low-temperature carbothermic reduction efficiency of iron ores,a static magnetic field with magnetic induction intensity of 1.0 T was introduced.An isothermal reduction experiment was conducted at 1223 K to study the low-temperature self-reduction characteristics of carbon-bearing pellets of Bayan Obo lean iron ores in the static magnetic field.Also,the acting mechanism of the magnetic field was explored from the perspective of the reduction process,reaction efficiency,phase composition,microstructure changes,and dynamic behavior of iron ores.The results showed that the magnetic field can increase the low-temperature reduction rate of carbon-bearing pellets of Bayan Obo lean iron ores.Under the conditions of reduction temperature of 1223 K,magnetic induction intensity of 1.0 T,and reduction time of 60 min,the reduction degree was 92.42%,1.65 times that without a magnetic field.The magnetic field promoted the replacement of Ca^(2+)and Fe^(2+),so that the hard-to-reduce iron-bearing silicates were reduced in the order of Fe2SiO_(4)→(Ca,Na)FeSiO_(4)→FeO→Fe.The magnetic field enabled loose minerals,more pores and cracks,and changes in the growth morphology and distribution position of metallic iron.Compared with the case under the non-magnetic condition,the metallic iron precipitated from the slag phase in a foliated shape,separated from the matrix iron oxides,and grew up at the junction of the slag phase and coke.The magnetic field significantly increased the interfacial chemical reaction rate of the carbothermic reduction of iron ores and reduced the internal diffusion resistance of gas in the product layer.Specifically,the interfacial chemical reaction rate increased by 138%and the internal diffusion coefficient increased by 309%.Therefore,the effect of the magnetic field on the internal diffusion resistance was the main cause for strengthening the low-temperature reduction of iron ores.
基金financially supported by Henan Provincial University Science and Technology Innovation Team(No.24IRTSTHN008)。
文摘Efficient bifunction electrocatalyst is extremely interesting for electrochemical overall water splitting(OWS).Herein,a new RuO_(2)-Ru/MoO_(2)@CC(RRM/CC)bifunctional electrocatalyst was prepared via a solid phase reaction strategy.To obtain a suitable precursor for SPR,MoS_(2)nanosheets and RuO_(2)nanoparticles(NPs)were sequentially loaded onto carbon cloth conductive substrate.Subsequently,the prepared RuO_(2)/MoS_(2)/CC precursor was sealed in a furnace and annealed in Ar to trigger the redox SPR.After SPR,active RuO_(2)-Ru/MoO_(2)units containing metal–metal oxide interfaces were formed on CC substrate uniformly.The optimized RRM/CC sample annealed at 400℃exhibited a overpotential of 13 m V for hydrogen evolution reaction(HER)and 231 mV for oxygen evolution reaction(OER)at 10 mA·cm^(-2)under alkaline condition,respectively,which can be deduced to the modulated electronic structure and unique hierarchica structure.In addition,a low cell voltage of 1.48 V for OWS was required at 10 mA·cm^(-2)under alkaline condition Meanwhile,RRM/CC exhibited excellent pH-independent durability.
基金supported by the Joint Research Funds in Astronomy under a cooperative agreement between the National Natural Science Foundation of China(NSFC)and the Chinese Academy of Sciences(Nos.U1931115 and U2031114)Scientific Research Fund of Hunan Provincial Education Department grant No.22A0099+1 种基金the support of the staff of the Xinglong 85 cm telescopepartially supported by the Open Project Program of the Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences。
文摘We present the first photometric and orbital period investigations for a neglected totally eclipsing contact binary IP Lyn.The photometric solutions derived from both ground-based and several surveys'observations suggest that it is a shallow contact binary with an extremely low mass ratio of 0.055.The weak asymmetry observed in our multiple band light curves can be interpreted as a result of an active cool spot on the primary.The absolute physical parameters were determined with the Gaia-distance-based method and checked by an empirical relation.Combining the eclipse timings collected from the literature and those derived from our and variable surveys'observations,we find that IP Lyn has been undergoing a secular orbital period increase for the past two decades,implying a mass transfer from the less massive secondary to the primary.By comparing the current parameters with the critical instability ones,we infer that IP Lyn is currently stable in spite of its relatively low mass ratio and orbital angular momentum.Finally,from a catalog of 117 extremely low mass ratio contact binaries,we find that their orbital angular momenta are significantly lower than those of the contact binaries with a relatively high mass ratio,suggesting they should be at the late evolutionary stage of a contact binary.
基金This study was funded by the National Natural Science Foundation of China(Grant No.51871118)the fund of the State Key Laboratory of Solidification Processing in NPU,(Grant No.SKLSP202204)the Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2022-ey15).
文摘The effects of Ta content(2.72wt.%,3.10wt.%and 4.00wt.%)on the solidification characteristics and mechanical properties of directionally solidified DZ411 Ni-based superalloys were investigated.It is found that the content of Mo decreases with the increase of Ta in liquid phase after directional solidification,indicating the addition of Ta can reduce the element segregation in alloys.The primary and secondary dendrite arm spacings(PDAS and SDAS)of the DZ411 alloy increase with the addition of Ta,which are consistent with the models by Hunt and Wagner.The increase of PDAS and SDAS can provide enough space for the growth of tertiary dendrite arms,which hinders the growth of unfavorably oriented primary dendrites.As a result,the addition of Ta facilitates the growth of favorably oriented dendrites.More MC carbides andγ-γ'eutectics are formed in the interdendritic regions,which is attributed to the segregation of Ta in the liquid phase.Furthermore,the degree of supersaturation of W,Mo inγmatrix increases with the increase of Ta,thus,the addition of Ta promotes the formation of TCP phase.The addition of Ta also increases the microhardness in both the primary dendrite and interdendritic regions of the alloy,and the microhardness of the primary dendrite is closer to that in interdendritic regions with the increase of Ta.
基金supported by the Natural Science Foundation of Liaoning Province,China(Grant No.2019JH/30100019)。
文摘In recent years,transition metal silicides have become the potential high temperature materials.The ternary silicide has attracted the attention of scientists and researchers.But their inherent brittle behaviors hinder their wide applications.In this work,we use the first-principles method to design four vacancy defects and discuss the effects of vacancy defects on the structural stability,mechanical properties,electronic and thermodynamic properties of hexagonal Cr;BSi;silicide.The data of lattice vibration and thermodynamic parameters indicate that the Cr;BSi;with different atomic vacancies can possess the structural stabilities.The different atomic vacancies change the mechanical properties and induce the Cr;BSi;to implement the brittle-to-ductile transition.The shear deformation resistance and volume deformation resistance of Cr;BSi;are weakened by different vacancy defects.But the brittleness behavior is remarkably improved.The structural stability and brittle-to-ductile transition of Cr;BSi;with different vacancies are explored by the electronic structures.Moreover,the thermal parameters indicate that the Cr;BSi;with vacancies exhibit different thermodynamic properties with temperature rising.
基金financially supported by the National Natural Science Foundation of China(No.22270509)。
文摘The packaging materials with cushioning performance are used to prevent the internal contents from being damaged by the impact and vibration of external forces.The polyurethane microcellular elastomers(PUMEs)can absorb energy through cell collapse and molecular chain creep.In this study,PUMEs with different densities were investigated by scanning electron microscopy,dynamic mechanical analysis and dynamic compression tests.PUMEs exhibited significant im pact resistance and the maximum peak stress attenuation ratio reached 73.33%.The protective equipment was made by PUME with the optimal density of 600 kg/m^(3),and then the acceleration sensing device installed with the same protective equipment fell from a height of 3,5 and 10 m to evaluate the energy-absorbing property and reusability of PUMEs.The results showed that PUMEs equipment reduced the peak acceleration of the device by 93.84%,with a maximum deviation of 9%between actual test and simulation,and shortened the impact time of first landing by 57.39%.In addition,the equipment PUMEs equipment could effectively reduce the stress on the protected items.
