Ultrathin 2D niobium oxide dichloride(NbOCl_(2))is an emerging member of the 2D ferroelectric material family with extensive potential to provide multifunctionality in electronic devices and nanophotonics elements.It ...Ultrathin 2D niobium oxide dichloride(NbOCl_(2))is an emerging member of the 2D ferroelectric material family with extensive potential to provide multifunctionality in electronic devices and nanophotonics elements.It exhibits negligible interlayer electronic coupling and significant excitonic behavior in the bulk state.Here we substantiate that NbOCl_(2) nanosheets can be exfoliated and effectively size-selected using controlled centrifugation techniques by the liquid phase exfoliation(LPE)method.Spectroscopic measurements displayed that the variations in dispersion were highly dependent on the nanosheet dimensions.The nanosheets seemed to be comparatively defect-free which will be further corroborated by high resolution transmission electron microscopy(HRTEM)and Raman analysis.The size selected nanosheets are unanticipated stable in isopropyl alcohol(IPA),possibly owing to the protective influence of a solvation shell.Additionally,the photothermal conversion response and photothermal stability of nanosized NbOCl_(2) were investigated.Our finding revealed that NbOCl_(2) possesses a robust photothermal agent property,boasting a photothermal conversion efficiency of more than 30%.This underscores its promising potential for various photothermal applications in different fields such as photothermal therapy and thermal energy conversion.展开更多
The authors regret the following changes to the paper:1.The following author is added to this article:Agnieszka Chmielewska-Wysockaa 2.Section 2.1:●“An aqueous binder”should be changed to“A solvent binder”.●Repl...The authors regret the following changes to the paper:1.The following author is added to this article:Agnieszka Chmielewska-Wysockaa 2.Section 2.1:●“An aqueous binder”should be changed to“A solvent binder”.●Replace“a composition of ethylene glycol monobutyl ether and ethylene glycol”by“50% binder saturation”.展开更多
A thin layer of TiO2 film was deposited on ITO surface via the liquid phase deposition （LPD） process. The photocurrent and electrochemical impedance spectroscopy （EIS） measurements indicated that the as-prepared L...A thin layer of TiO2 film was deposited on ITO surface via the liquid phase deposition （LPD） process. The photocurrent and electrochemical impedance spectroscopy （EIS） measurements indicated that the as-prepared LPD TiO2/ITO film had an excellent photoelectrochemical performance, which showed a sensitive and rapid response to the UV irradiation. The photogenerated electron-hole pairs could be effectively separated by applying an external bias to the TiO2 film electrode. The LPD TiO2/ITO film was employed to study the photoelectrocatalytic （PEC） degradation of 4-aminoantipyrine. Compared with other techniques, the PEC technique based on such a LPD film electrode had a synergetic effect for 4-aminoantipyrine degradation. When the applied bias potential was＋0.8 V and the supporting electrolyte concentration of Na2SO4 was 0.1 mol/L, the highest degradation efficiency within 120 min could reach 95%for 0.1 mmol/L 4-aminoantipyrine solution at pH 2.0.展开更多
The carbon-coated monoclinic Li3V2(PO4)3(LVP) cathode materials were successfully synthesized by liquid phase method using PEG as reducing agent and carbon source. The effects of relative molecular mass of PEG on the ...The carbon-coated monoclinic Li3V2(PO4)3(LVP) cathode materials were successfully synthesized by liquid phase method using PEG as reducing agent and carbon source. The effects of relative molecular mass of PEG on the properties of Li3V2(PO4)3/C were evaluated by X-ray diffraction(XRD), scanning electron microscope(SEM) and electrochemical performance tests. The SEM images show that smaller size particles are obtained by adding larger and smaller PEGs. The electrochemical cycling of Li3V2(PO4)3/C prepared by both PEG200 and PEG20 k has a high initial discharge capacity of 131.1 mA·h/g at 0.1C during 3.0-4.2 V, and delivers a reversible discharge capacity of 123.6 m A·h/g over 30 cycles, which is better than that of other samples. The improvement in electrochemical performance is caused by its improved lithium ion diffusion coefficient for the macroporous morphology, which is verified by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS).展开更多
Transient liquid phase（TLP） bonding of IN738 LC superalloy was carried out using a rapidly solidified MBF-15 Ni-based foil. The effects of bonding temperature（1130–1170 °C） and time（5–120 min） as well as ...Transient liquid phase（TLP） bonding of IN738 LC superalloy was carried out using a rapidly solidified MBF-15 Ni-based foil. The effects of bonding temperature（1130–1170 °C） and time（5–120 min） as well as foil thickness（35–140 μm） were studied on the microstructure of joint region and its mechanical properties. The solidification sequence in the joint region was found to be（i） formation of γ solid solution in the isothermally solidified zone, followed by（ii） ternary eutectic of γ ＋ Ni3 B ＋ Cr B, and finally（iii） binary eutectic of γ ＋ Ni3 Si in the athermally solidified zone. Fine Ni3 Si particles were also formed via a solid state transformation within the γ matrix in the vicinity of eutectic products. A deviation of isothermal solidification kinetics from the standard parabolic TLP model was observed by increasing the bonding temperature to 1170 °C, which resulted in the formation of eutectic constituents at the joint centerline.The analysis of mechanical and fractographic test results revealed that the samples with complete isothermal solidification exhibit the highest shear strength, whereas the hard eutectic constituents act as preferential failure sites and lead to a significant reduction in the joint shear strength in samples with incomplete isothermal solidification.展开更多
The kinetic characteristics of W grain growth operated by diffusion controlled Oswald ripening （DOR） during liquid phase sintering were studied. A liquid phase sintering of W-15wt%Cu was carried out by pushing compa...The kinetic characteristics of W grain growth operated by diffusion controlled Oswald ripening （DOR） during liquid phase sintering were studied. A liquid phase sintering of W-15wt%Cu was carried out by pushing compacts into a furnace at the moment when the temperature increased to 1340℃ for different sintering times. The results show that liquid phase sintering produces the compacts with considerably low relative density and inversely, rather high homogeneity. On the basis of the data extracted from the SEM images, the kinetic equation of W grain growth, G^n = G0^n ＋ kt, is determined in which the grain growth exponent n is 3 and the grain growth rate constant k is 0.15 μm^3/s. The cumulative normalized grain size distributions produced by different sintering times show self-similar. The cumulative distribution function is extracted from the curves by non-linear fitting. In addition, the sintering kinetic characteristics of W-15wt%Cu compacts were also investigated.展开更多
Velocities of solid phase and liquid phase in debris flow are one key problem to research on impact and abrasion mechanism of banks and control structures under action of debris flow. Debris flow was simplified as two...Velocities of solid phase and liquid phase in debris flow are one key problem to research on impact and abrasion mechanism of banks and control structures under action of debris flow. Debris flow was simplified as two-phase liquid composed of solid phase with the same diameter particles and liquid phase with the same mechanical features. Assume debris flow was one-dimension two-phase liquid moving to one direction, then general equations of velocities of solid phase and liquid phase were founded in two-phase theory. Methods to calculate average pressures, volume forces and surface forces of debris flow control volume were established. Specially, surface forces were ascertained using Bingham＇s rheology equation of liquid phase and Bagnold＇s testing results about interaction between particles of solid phase. Proportional coefficient of velocities between liquid phase and solid phase was put forward, meanwhile, divergent coefficient between theoretical velocity and real velocity of solid phase was provided too. To state succinctly before, method to calculate velocities of solid phase and liquid phase was obtained through solution to general equations. The method is suitable for both viscous debris flow and thin debris flow. Additionally, velocities every phase can be identified through analyzing deposits in-situ after occurring of debris flow. It is obvious from engineering case the result in the method is consistent to that in real-time field observation.展开更多
The effect of Sm-rich liquid phase （Sm2Co3） on magnetic properties and microstructure of 2：17-type Sin-Co magnet was studied. Three phases existed in liquid phase ingot, and took on white, dark grey and grey, respe...The effect of Sm-rich liquid phase （Sm2Co3） on magnetic properties and microstructure of 2：17-type Sin-Co magnet was studied. Three phases existed in liquid phase ingot, and took on white, dark grey and grey, respectively. It was found that the composition of the grey area was similar to the nominal one. Our results indicated that the optimal composition was obtained at 3 wt.% liquid phase added, and the magnetic properties were B^I 1.58 kGs, Hci〉26 kOe, （BH）m=29.51 MGOe. Br increased by 3%, Hci was 13 times larger, and （B/-/）m was 6 times bigger than none liquid phase magnets. Moreover, with the aging time decreasing from 20 to 8 h, the squareness of the demagnetization curves got better, while the coercivity of the samples decreased. It revealed that Sm（Co,Cu）5 phase also precipitated at particle boundaries. It maybe also enhanced the coercivity.展开更多
A convenient,cost-effective and fast method using dynamic microwave-assisted extraction and liquid phase microextraction based on the solidification of a floating drop was proposed to analyze organochlorine pesticides...A convenient,cost-effective and fast method using dynamic microwave-assisted extraction and liquid phase microextraction based on the solidification of a floating drop was proposed to analyze organochlorine pesticides in grains including rice,maize and millet.Twelve samples can be processed simultaneously in the method.During the extraction process,10%acetonitrile-water solutions containing 110μL of n-hexadecane were used to extract organochlorine pesticides.Subsequently,1.0 g sodium chloride was placed in the extract,and then centrifuged and cooled.The n-hexadecane drops containing the analytes were solidifi ed and transferred for determination by gas chromatography-electron capture detector without any further filtration or cleaning process.Limits of detection for organochlorine pesticides were 0.97–1.01μg/kg and the RSDs were in the range of 2.6%–8.5%.The developed technology has succeeded in analyzing six real grains samples and the recoveries of the organochlorine pesticides were 72.2%–94.3%.Compared with the published extraction methods,the developed method was used to analyze organochlorine pesticides in grains,being more environmentally friendly,which is suitable for the daily determination of organochlorine pesticides.展开更多
With rapid development of the pellet production under the background of green development,high-quality iron concentrates were gradually exhausted;thus,using high-silica iron concentrates was expected to be a promising...With rapid development of the pellet production under the background of green development,high-quality iron concentrates were gradually exhausted;thus,using high-silica iron concentrates was expected to be a promising way to relieve resource pressure for pellet production.However,increasing the proportion of high-silica acid pellets into the furnace led to worse blast furnace slag,and the metallurgical properties of high-silica pellets were imperfect.To understand the reciprocal effects of basicity(CaO/SiO_(2))and MgO content on the properties of the high-silica pellets,the phase compositions and microstructure were investigated using X-ray diffraction and scanning electron microscope,equipped with energy dispersive X-ray spectrometry.The results indicated that simply increasing MgO content from O to 2.50 wt.%could decrease the reduction swelling index,but the compressive strength rapidly declined due to the formation of magnesioferrite.However,adding CaO to 2.50 wt.%MgO pellets greatly improved the pellet qualities,which could be attributed to a substantial increase in the amount of high-melting-point silicate liquid phase.展开更多
Gangue existing states largely affect the high-temperature characteristics of iron ores. Using a micro-sintering method and scan- ning electron microscopy, the effects of gangue content, gangue type, and gangue size o...Gangue existing states largely affect the high-temperature characteristics of iron ores. Using a micro-sintering method and scan- ning electron microscopy, the effects of gangue content, gangue type, and gangue size on the assimilation characteristics and fluidity of liquid phase of five different iron ores were analyzed in this study. Next, the mechanism based on the reaction between gangues and sintering mate- dais was unraveled. The results show that, as the SiO2 levels increase in the iron ores, the lowest assimilation temperature （LAT） decreases, whereas the index of fluidity of liquid phase （IFL） increases. Below 1.5wt%, Al2O3 benefits the assimilation reaction, but higher concentra- tions proved detrimental. Larger quartz particles increase the SiO2 levels at the local reaction interface between the iron ore and CaO, thereby reducing the LAT. Quartz-gibbsite is more conductive to assimilation than kaolin. Quartz-gibbsite and kaolin gangues encourage the forma- tion of liquid-phase low-Al2O3-SFCA with high IFL and high-Al2O3-SFCA with low IFL, respectively.展开更多
A single-drop liquid phase micro-extraction procedure using 1-butyl-3-methylimidazolium hexafluorophosphate （[C4MIM][PF6]） was demonstrated for the sensitive determination of four phenols in water samples. Under the...A single-drop liquid phase micro-extraction procedure using 1-butyl-3-methylimidazolium hexafluorophosphate （[C4MIM][PF6]） was demonstrated for the sensitive determination of four phenols in water samples. Under the optimized conditions, the linear range of proposed method was excellent in the range of 0.5-100 μg·L^-1, the reproducibility （RSD, n=6） were in the range 5.4%-8.9% and detection limits （S/N=3） were 0.3, 0.3, 0.5 and 0.5 μg·L^-1 for 2, 4-dichlorophenol, 2-naphthol, 2-nitrophenol and 4-chlorophenol, respectively. The experimental results indicated that the effect of complex matrices natural water samples could be resolved with addition of sodium ethylene diamine tetracetate （EDTA） into the samples. Excellent spiked recoveries were achieved for these four phenols ranged from 86.2%-114.9 %. All these facts demonstrated that the proposed method with merits of low cost, simplicity and easy operating would be a competitive alternative procedure for the determination of such compounds at trace level.展开更多
InAsSb epilayers with a cutoff wavelength of 4.8 μm have been successfully grown on InAs substrates by one-step liquid phase epitaxy （LPE） technology. The epilayers were characterized by X-ray diffraction （XRD）, ...InAsSb epilayers with a cutoff wavelength of 4.8 μm have been successfully grown on InAs substrates by one-step liquid phase epitaxy （LPE） technology. The epilayers were characterized by X-ray diffraction （XRD）, Fourier transform infrared （PTIR） transmittance measurements and scanning electron microscopy （SEM）. The influence of different growth conditions on the optical and structural properties of the materials was studied. The results revealed that the good crystalline quality, mirror smooth surface and flat interface of InAsSb epilayers were achieved. They benefited from optimized growth conditions, i.e., sufficient homogeneity of the growth melt and a very slow cooling rate.展开更多
Liquid phase epitaxy （LPE） is a mature technology. Early experiments on single magnetic crystal films fabricated by LPE were focused mainly on thick films for microwave and magneto-optical devices. The LPE is an exc...Liquid phase epitaxy （LPE） is a mature technology. Early experiments on single magnetic crystal films fabricated by LPE were focused mainly on thick films for microwave and magneto-optical devices. The LPE is an excellent way to make a thick film, low damping magnetic garnet film and high-quality magneto-optical material. Today, the principal challenge in the applied material is to create sub-micrometer devices by using modern photolithography technique. Until now the magnetic garnet films fabricated by LPE still show the best quality even on a nanoscale （about 100 nm）, which was considered to be impossible for LPE method.展开更多
The open-cell Al foam core sandwiches（AFCSs） were successfully fabricated by using a specially designed Zn-Al-Cu based filler alloy via vibration aided liquid phase bonding method.The effects of the vibration on the...The open-cell Al foam core sandwiches（AFCSs） were successfully fabricated by using a specially designed Zn-Al-Cu based filler alloy via vibration aided liquid phase bonding method.The effects of the vibration on the bonding seam were investigated and the bonding strength between Al foam core and solid Al alloy face sheet was tested by shearing tests.The results show that vibration can significantly improve the quality of the bonding and the shearing strength of the bonding seam,which implies that this joining method has a good potential in practical applications.展开更多
In this study, a two-step heating process is introduced for transient liquid phase ( TLP) diffusion bonding fo r sound joints with T91 heat resistant steels. At first, a short-time higher temperature heating ...In this study, a two-step heating process is introduced for transient liquid phase ( TLP) diffusion bonding fo r sound joints with T91 heat resistant steels. At first, a short-time higher temperature heating step is addressed to melt the interlayer, followed by the second step to complete isothermal solidification at a low temperature. The most critical feature of our new method is producing a non-planar interface at the T9/ heat resistant steels joint. We propose a transitional liquid phase bonding of T91 heat resistant steels by this approach. Since joint microstructures have been studied, we tested the tensile strength to assess joint mechanical property. The result indicates that the solidified bond may contain a primary solid-solution, similar composition to the parent metal and free from precipitates. Joint tensile strength of the joint is not lower than parent materials. Joint bend's strengths are enhanced due to the higher metal-to-metal junction producing a non-planar bond lines. Nevertheless, the traditional transient liquid phase diffusion bonding produces planar ones. Bonding parameters of new process are 1 260 °C for 0. 5 min and 1 230 °C fo r 4 min.展开更多
Transient liquid phase bonding of two dissimilar alloys Al 2024 and Ti?6Al?4V using Cu?22%Zn interlayer was carried out at 510 °C under vacuum of 0.01 Pa for various bonding time. In order to characterize the mic...Transient liquid phase bonding of two dissimilar alloys Al 2024 and Ti?6Al?4V using Cu?22%Zn interlayer was carried out at 510 °C under vacuum of 0.01 Pa for various bonding time. In order to characterize the microstructure evolution in the joint zone, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) were applied. The results show that joint formation is attributed to the solid-state diffusion of Cu and Zn into Ti?6Al?4V and Al 2024 alloys followed by eutectic formation and isothermal solidification along the Cu?Zn/Al 2024 interface. The hardness of the joints at the interface increases with an increase in bonding time which can be attributed to formation of intermetallic compounds such as Al2Cu, TiCu3, Al4.2Cu3.2Zn0.7, Al0.71Zn0.29, Ti2Cu, TiAl3 and TiZn16 in the joint zone. Moreover, shear strength of the joint reaches the highest value of 37 MPa at bonding time of 60 min.展开更多
In order to investigate the microstructure evolution and gain complete isothermal solidification time, transient liquid phase （TLP） bonding of IN-738LC superalloy was carried out using powdered AMS 4777 as the fille...In order to investigate the microstructure evolution and gain complete isothermal solidification time, transient liquid phase （TLP） bonding of IN-738LC superalloy was carried out using powdered AMS 4777 as the filler metal. The influence of gap size and bonding time on the joints was investigated. For example, complete isothermal solidification time for 40μm gap size was obtained as 45 min. In the case of lack of completion of isothermal solidification step, the remained molten interlayer cooled in the bonding zone under non-equilibrium condition andγ–γ′ eutectic phase formed in that area. The relationship between gap size and holding time was not linear. With the increase in gap size, eutectic phase width became thicker. In the diffusion affected zone, a much larger amount of alloying elements were observed reaching a peak. These peaks might be due to the formation of boride or silicide intermetallic. With the increase in gap size, the time required for bonding will increase, so the alloying elements have more time for diffusion and distribution in farther areas. As a result, concentrations of alloying elements decreased slightly with the increase in the gap size. The present bi-phasic model did not properly predict the complete isothermal solidification time for IN-738LC-AMS 4777-IN-738LC TLP bonding system.展开更多
In this paper,shorter residence time（a few minutes）with high yield in the trickle bed process for per- acetic acid synthesis by acetaldehyde liquid phase oxidation can be realized on the selected packing material SA...In this paper,shorter residence time（a few minutes）with high yield in the trickle bed process for per- acetic acid synthesis by acetaldehyde liquid phase oxidation can be realized on the selected packing material SA-5118.For acetaldehyde in acetone with ferric ion as catalyst,the optimized process conditions were presented. The main factors influencing the yield,selectivity and conversion are residence time,temperature and acetaldehyde concentration,respectively.The temperature range checked is from 30 to 65℃.High yield of 81.53%with high se- lectivity of 91.84%can be obtained at higher temperature of 55℃when the residence time is 5.5min and the acet- aldehyde concentration is 9.85%（by mass）.And there is a critical acetaldehyde concentration point（Cccp）between 18%and 19.5%（by mass）.At temperature less than 55℃,the highest yield to peracetic acid at each temperature level increases with temperature when the acetaldehyde concentration is below Cccp and decreases with temperature when the acetaldehyde concentration is above Cccp.展开更多
This study focuses on the transient liquid phase(TLP)bonding of DD5 single-crystal superalloy to Cr Co Nibased medium-entropy alloy(MEA)using a BNi-2 filler alloy.The microstructure and mechanical properties of the TL...This study focuses on the transient liquid phase(TLP)bonding of DD5 single-crystal superalloy to Cr Co Nibased medium-entropy alloy(MEA)using a BNi-2 filler alloy.The microstructure and mechanical properties of the TLP-bonded DD5/MEA joint were evaluated,and the microstructural evolution mechanism was investigated.The formation of the isothermal solidification zone(ISZ)depended on the diffusion of the melting-point depressants(Si and B elements)from the liquid filler into the DD5 and MEA substrates,as well as the dissolution of the substrates.Boron diffused along theγchannel of DD5 and reacted to form M_(5)B_(3)boride,herein referred to as the diffusion-affected zone(DAZ I).Similarly,the Cr_(5)B_(3)boride precipitated in the Ni-rich MEA matrix adjacent to the MEA substrate(i.e.,DAZ II).Additionally,a coherent orientation of[0]_(BCY)//[011]_(FCC)and(002)_(BCY)//(200)_(FCC)was detected between M_(5)B_(3)boride with a body-centered tetragonal(BCT)structure and the face-centered cubic(FCC)matrix.The performance of the joint was dominated by the properties of the bonding seam.As the bonding time increased from 20to 80 min,the athermal solidification zone(including eutectic microstructure)was gradually replaced by the ISZ exhibiting excellent plastic deformation capability,and the shear strength of the joint was improved.The maximum shear strength(752 MPa)was achieved when the eutectic-free joint was bonded at 1050℃ for 80 min.The fracture morphology revealed a mixture mode,indicating the initiation of cracks in the DAZ II,mainly propagating in the ISZ,and passing through the DAZ I.展开更多
基金Projects(62275275,11904239)supported by the National Natural Science Foundation of ChinaProjects(2021JJ40709,2022JJ20080)supported by the Natural Science Foundation of Hunan Province,China。
文摘Ultrathin 2D niobium oxide dichloride(NbOCl_(2))is an emerging member of the 2D ferroelectric material family with extensive potential to provide multifunctionality in electronic devices and nanophotonics elements.It exhibits negligible interlayer electronic coupling and significant excitonic behavior in the bulk state.Here we substantiate that NbOCl_(2) nanosheets can be exfoliated and effectively size-selected using controlled centrifugation techniques by the liquid phase exfoliation(LPE)method.Spectroscopic measurements displayed that the variations in dispersion were highly dependent on the nanosheet dimensions.The nanosheets seemed to be comparatively defect-free which will be further corroborated by high resolution transmission electron microscopy(HRTEM)and Raman analysis.The size selected nanosheets are unanticipated stable in isopropyl alcohol(IPA),possibly owing to the protective influence of a solvation shell.Additionally,the photothermal conversion response and photothermal stability of nanosized NbOCl_(2) were investigated.Our finding revealed that NbOCl_(2) possesses a robust photothermal agent property,boasting a photothermal conversion efficiency of more than 30%.This underscores its promising potential for various photothermal applications in different fields such as photothermal therapy and thermal energy conversion.
文摘The authors regret the following changes to the paper:1.The following author is added to this article:Agnieszka Chmielewska-Wysockaa 2.Section 2.1:●“An aqueous binder”should be changed to“A solvent binder”.●Replace“a composition of ethylene glycol monobutyl ether and ethylene glycol”by“50% binder saturation”.
基金Projects(12JJ3013,11JJ5010,10JJ5002)supported by the Natural Science Foundation of Hunan Province,ChinaProject(2013CL04)supported by the Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation,Changsha University of Science and Technology,ChinaProject(2011RS4069)supported by the Planned Science and Technology Program of Hunan Province,China
文摘A thin layer of TiO2 film was deposited on ITO surface via the liquid phase deposition （LPD） process. The photocurrent and electrochemical impedance spectroscopy （EIS） measurements indicated that the as-prepared LPD TiO2/ITO film had an excellent photoelectrochemical performance, which showed a sensitive and rapid response to the UV irradiation. The photogenerated electron-hole pairs could be effectively separated by applying an external bias to the TiO2 film electrode. The LPD TiO2/ITO film was employed to study the photoelectrocatalytic （PEC） degradation of 4-aminoantipyrine. Compared with other techniques, the PEC technique based on such a LPD film electrode had a synergetic effect for 4-aminoantipyrine degradation. When the applied bias potential was＋0.8 V and the supporting electrolyte concentration of Na2SO4 was 0.1 mol/L, the highest degradation efficiency within 120 min could reach 95%for 0.1 mmol/L 4-aminoantipyrine solution at pH 2.0.
基金Project(2014CB643406)supported by the National Basic Research Program of China
文摘The carbon-coated monoclinic Li3V2(PO4)3(LVP) cathode materials were successfully synthesized by liquid phase method using PEG as reducing agent and carbon source. The effects of relative molecular mass of PEG on the properties of Li3V2(PO4)3/C were evaluated by X-ray diffraction(XRD), scanning electron microscope(SEM) and electrochemical performance tests. The SEM images show that smaller size particles are obtained by adding larger and smaller PEGs. The electrochemical cycling of Li3V2(PO4)3/C prepared by both PEG200 and PEG20 k has a high initial discharge capacity of 131.1 mA·h/g at 0.1C during 3.0-4.2 V, and delivers a reversible discharge capacity of 123.6 m A·h/g over 30 cycles, which is better than that of other samples. The improvement in electrochemical performance is caused by its improved lithium ion diffusion coefficient for the macroporous morphology, which is verified by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS).
文摘Transient liquid phase（TLP） bonding of IN738 LC superalloy was carried out using a rapidly solidified MBF-15 Ni-based foil. The effects of bonding temperature（1130–1170 °C） and time（5–120 min） as well as foil thickness（35–140 μm） were studied on the microstructure of joint region and its mechanical properties. The solidification sequence in the joint region was found to be（i） formation of γ solid solution in the isothermally solidified zone, followed by（ii） ternary eutectic of γ ＋ Ni3 B ＋ Cr B, and finally（iii） binary eutectic of γ ＋ Ni3 Si in the athermally solidified zone. Fine Ni3 Si particles were also formed via a solid state transformation within the γ matrix in the vicinity of eutectic products. A deviation of isothermal solidification kinetics from the standard parabolic TLP model was observed by increasing the bonding temperature to 1170 °C, which resulted in the formation of eutectic constituents at the joint centerline.The analysis of mechanical and fractographic test results revealed that the samples with complete isothermal solidification exhibit the highest shear strength, whereas the hard eutectic constituents act as preferential failure sites and lead to a significant reduction in the joint shear strength in samples with incomplete isothermal solidification.
基金This work was financially supported by the National Natural Science Foundation of China (No. 50174007).
文摘The kinetic characteristics of W grain growth operated by diffusion controlled Oswald ripening （DOR） during liquid phase sintering were studied. A liquid phase sintering of W-15wt%Cu was carried out by pushing compacts into a furnace at the moment when the temperature increased to 1340℃ for different sintering times. The results show that liquid phase sintering produces the compacts with considerably low relative density and inversely, rather high homogeneity. On the basis of the data extracted from the SEM images, the kinetic equation of W grain growth, G^n = G0^n ＋ kt, is determined in which the grain growth exponent n is 3 and the grain growth rate constant k is 0.15 μm^3/s. The cumulative normalized grain size distributions produced by different sintering times show self-similar. The cumulative distribution function is extracted from the curves by non-linear fitting. In addition, the sintering kinetic characteristics of W-15wt%Cu compacts were also investigated.
基金Project supported by the Talent Fund of the Ministry of Communication of China(No.95050508) the Fund of Western Communication of China(No.200332822047) the Key Science Fund of the Ministry of Communication of China(No.95060233)
文摘Velocities of solid phase and liquid phase in debris flow are one key problem to research on impact and abrasion mechanism of banks and control structures under action of debris flow. Debris flow was simplified as two-phase liquid composed of solid phase with the same diameter particles and liquid phase with the same mechanical features. Assume debris flow was one-dimension two-phase liquid moving to one direction, then general equations of velocities of solid phase and liquid phase were founded in two-phase theory. Methods to calculate average pressures, volume forces and surface forces of debris flow control volume were established. Specially, surface forces were ascertained using Bingham＇s rheology equation of liquid phase and Bagnold＇s testing results about interaction between particles of solid phase. Proportional coefficient of velocities between liquid phase and solid phase was put forward, meanwhile, divergent coefficient between theoretical velocity and real velocity of solid phase was provided too. To state succinctly before, method to calculate velocities of solid phase and liquid phase was obtained through solution to general equations. The method is suitable for both viscous debris flow and thin debris flow. Additionally, velocities every phase can be identified through analyzing deposits in-situ after occurring of debris flow. It is obvious from engineering case the result in the method is consistent to that in real-time field observation.
基金supported by the National Natural Science Foundation of China (50871032)National High Technology Research and Development Program of ChinaProgram of Beijing Municipal Science & Technology
文摘The effect of Sm-rich liquid phase （Sm2Co3） on magnetic properties and microstructure of 2：17-type Sin-Co magnet was studied. Three phases existed in liquid phase ingot, and took on white, dark grey and grey, respectively. It was found that the composition of the grey area was similar to the nominal one. Our results indicated that the optimal composition was obtained at 3 wt.% liquid phase added, and the magnetic properties were B^I 1.58 kGs, Hci〉26 kOe, （BH）m=29.51 MGOe. Br increased by 3%, Hci was 13 times larger, and （B/-/）m was 6 times bigger than none liquid phase magnets. Moreover, with the aging time decreasing from 20 to 8 h, the squareness of the demagnetization curves got better, while the coercivity of the samples decreased. It revealed that Sm（Co,Cu）5 phase also precipitated at particle boundaries. It maybe also enhanced the coercivity.
基金The study was financially supported by the National Science and Technology Support Program of China(Grant No.2013BAD16B08).
文摘A convenient,cost-effective and fast method using dynamic microwave-assisted extraction and liquid phase microextraction based on the solidification of a floating drop was proposed to analyze organochlorine pesticides in grains including rice,maize and millet.Twelve samples can be processed simultaneously in the method.During the extraction process,10%acetonitrile-water solutions containing 110μL of n-hexadecane were used to extract organochlorine pesticides.Subsequently,1.0 g sodium chloride was placed in the extract,and then centrifuged and cooled.The n-hexadecane drops containing the analytes were solidifi ed and transferred for determination by gas chromatography-electron capture detector without any further filtration or cleaning process.Limits of detection for organochlorine pesticides were 0.97–1.01μg/kg and the RSDs were in the range of 2.6%–8.5%.The developed technology has succeeded in analyzing six real grains samples and the recoveries of the organochlorine pesticides were 72.2%–94.3%.Compared with the published extraction methods,the developed method was used to analyze organochlorine pesticides in grains,being more environmentally friendly,which is suitable for the daily determination of organochlorine pesticides.
基金the National Natural Science Foundation of China(Nos.U1960114 and 51574283)the Fundamental Research Funds for theCentraUlniversities(2021XQLH029).
文摘With rapid development of the pellet production under the background of green development,high-quality iron concentrates were gradually exhausted;thus,using high-silica iron concentrates was expected to be a promising way to relieve resource pressure for pellet production.However,increasing the proportion of high-silica acid pellets into the furnace led to worse blast furnace slag,and the metallurgical properties of high-silica pellets were imperfect.To understand the reciprocal effects of basicity(CaO/SiO_(2))and MgO content on the properties of the high-silica pellets,the phase compositions and microstructure were investigated using X-ray diffraction and scanning electron microscope,equipped with energy dispersive X-ray spectrometry.The results indicated that simply increasing MgO content from O to 2.50 wt.%could decrease the reduction swelling index,but the compressive strength rapidly declined due to the formation of magnesioferrite.However,adding CaO to 2.50 wt.%MgO pellets greatly improved the pellet qualities,which could be attributed to a substantial increase in the amount of high-melting-point silicate liquid phase.
基金financially supported by the Fundamental Research Funds for the Central Universities of China(No.FRF-MP-12-003B)
文摘Gangue existing states largely affect the high-temperature characteristics of iron ores. Using a micro-sintering method and scan- ning electron microscopy, the effects of gangue content, gangue type, and gangue size on the assimilation characteristics and fluidity of liquid phase of five different iron ores were analyzed in this study. Next, the mechanism based on the reaction between gangues and sintering mate- dais was unraveled. The results show that, as the SiO2 levels increase in the iron ores, the lowest assimilation temperature （LAT） decreases, whereas the index of fluidity of liquid phase （IFL） increases. Below 1.5wt%, Al2O3 benefits the assimilation reaction, but higher concentra- tions proved detrimental. Larger quartz particles increase the SiO2 levels at the local reaction interface between the iron ore and CaO, thereby reducing the LAT. Quartz-gibbsite is more conductive to assimilation than kaolin. Quartz-gibbsite and kaolin gangues encourage the forma- tion of liquid-phase low-Al2O3-SFCA with high IFL and high-Al2O3-SFCA with low IFL, respectively.
文摘A single-drop liquid phase micro-extraction procedure using 1-butyl-3-methylimidazolium hexafluorophosphate （[C4MIM][PF6]） was demonstrated for the sensitive determination of four phenols in water samples. Under the optimized conditions, the linear range of proposed method was excellent in the range of 0.5-100 μg·L^-1, the reproducibility （RSD, n=6） were in the range 5.4%-8.9% and detection limits （S/N=3） were 0.3, 0.3, 0.5 and 0.5 μg·L^-1 for 2, 4-dichlorophenol, 2-naphthol, 2-nitrophenol and 4-chlorophenol, respectively. The experimental results indicated that the effect of complex matrices natural water samples could be resolved with addition of sodium ethylene diamine tetracetate （EDTA） into the samples. Excellent spiked recoveries were achieved for these four phenols ranged from 86.2%-114.9 %. All these facts demonstrated that the proposed method with merits of low cost, simplicity and easy operating would be a competitive alternative procedure for the determination of such compounds at trace level.
基金provided by the National Natural Science Foundation of China (No. 60777022)the Program for Young Excellent Tal-ents in Tongji University
文摘InAsSb epilayers with a cutoff wavelength of 4.8 μm have been successfully grown on InAs substrates by one-step liquid phase epitaxy （LPE） technology. The epilayers were characterized by X-ray diffraction （XRD）, Fourier transform infrared （PTIR） transmittance measurements and scanning electron microscopy （SEM）. The influence of different growth conditions on the optical and structural properties of the materials was studied. The results revealed that the good crystalline quality, mirror smooth surface and flat interface of InAsSb epilayers were achieved. They benefited from optimized growth conditions, i.e., sufficient homogeneity of the growth melt and a very slow cooling rate.
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFA0300801)the National Natural Science Foundation of China(Grant Nos.51702042,61734002,61571079,51572042,and 61471096)+1 种基金the International Science&Technology Cooperation Program of China(Grant No.2015DFR50870)the Sichuan Science and Technology Support Project,China(Grant Nos.2016GZ0250 and 2017JY0002)
文摘Liquid phase epitaxy （LPE） is a mature technology. Early experiments on single magnetic crystal films fabricated by LPE were focused mainly on thick films for microwave and magneto-optical devices. The LPE is an excellent way to make a thick film, low damping magnetic garnet film and high-quality magneto-optical material. Today, the principal challenge in the applied material is to create sub-micrometer devices by using modern photolithography technique. Until now the magnetic garnet films fabricated by LPE still show the best quality even on a nanoscale （about 100 nm）, which was considered to be impossible for LPE method.
基金support provided by the National Program on Key Basic Research Project of China (No. 2006CB601201)supports from the Research Fund for Doctoral Program of Higher Education of China (No. 200802941010)+1 种基金the Natural Science Foundation of Hohai University (No. 2008428011)the Scientific Research Startup Fund of Hohai University(No. 2084140801109)
文摘The open-cell Al foam core sandwiches（AFCSs） were successfully fabricated by using a specially designed Zn-Al-Cu based filler alloy via vibration aided liquid phase bonding method.The effects of the vibration on the bonding seam were investigated and the bonding strength between Al foam core and solid Al alloy face sheet was tested by shearing tests.The results show that vibration can significantly improve the quality of the bonding and the shearing strength of the bonding seam,which implies that this joining method has a good potential in practical applications.
基金supported by the Natural Science Foundation of Henan Province(Grant No.152107000047)
文摘In this study, a two-step heating process is introduced for transient liquid phase ( TLP) diffusion bonding fo r sound joints with T91 heat resistant steels. At first, a short-time higher temperature heating step is addressed to melt the interlayer, followed by the second step to complete isothermal solidification at a low temperature. The most critical feature of our new method is producing a non-planar interface at the T9/ heat resistant steels joint. We propose a transitional liquid phase bonding of T91 heat resistant steels by this approach. Since joint microstructures have been studied, we tested the tensile strength to assess joint mechanical property. The result indicates that the solidified bond may contain a primary solid-solution, similar composition to the parent metal and free from precipitates. Joint tensile strength of the joint is not lower than parent materials. Joint bend's strengths are enhanced due to the higher metal-to-metal junction producing a non-planar bond lines. Nevertheless, the traditional transient liquid phase diffusion bonding produces planar ones. Bonding parameters of new process are 1 260 °C for 0. 5 min and 1 230 °C fo r 4 min.
文摘Transient liquid phase bonding of two dissimilar alloys Al 2024 and Ti?6Al?4V using Cu?22%Zn interlayer was carried out at 510 °C under vacuum of 0.01 Pa for various bonding time. In order to characterize the microstructure evolution in the joint zone, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) were applied. The results show that joint formation is attributed to the solid-state diffusion of Cu and Zn into Ti?6Al?4V and Al 2024 alloys followed by eutectic formation and isothermal solidification along the Cu?Zn/Al 2024 interface. The hardness of the joints at the interface increases with an increase in bonding time which can be attributed to formation of intermetallic compounds such as Al2Cu, TiCu3, Al4.2Cu3.2Zn0.7, Al0.71Zn0.29, Ti2Cu, TiAl3 and TiZn16 in the joint zone. Moreover, shear strength of the joint reaches the highest value of 37 MPa at bonding time of 60 min.
文摘In order to investigate the microstructure evolution and gain complete isothermal solidification time, transient liquid phase （TLP） bonding of IN-738LC superalloy was carried out using powdered AMS 4777 as the filler metal. The influence of gap size and bonding time on the joints was investigated. For example, complete isothermal solidification time for 40μm gap size was obtained as 45 min. In the case of lack of completion of isothermal solidification step, the remained molten interlayer cooled in the bonding zone under non-equilibrium condition andγ–γ′ eutectic phase formed in that area. The relationship between gap size and holding time was not linear. With the increase in gap size, eutectic phase width became thicker. In the diffusion affected zone, a much larger amount of alloying elements were observed reaching a peak. These peaks might be due to the formation of boride or silicide intermetallic. With the increase in gap size, the time required for bonding will increase, so the alloying elements have more time for diffusion and distribution in farther areas. As a result, concentrations of alloying elements decreased slightly with the increase in the gap size. The present bi-phasic model did not properly predict the complete isothermal solidification time for IN-738LC-AMS 4777-IN-738LC TLP bonding system.
文摘In this paper,shorter residence time（a few minutes）with high yield in the trickle bed process for per- acetic acid synthesis by acetaldehyde liquid phase oxidation can be realized on the selected packing material SA-5118.For acetaldehyde in acetone with ferric ion as catalyst,the optimized process conditions were presented. The main factors influencing the yield,selectivity and conversion are residence time,temperature and acetaldehyde concentration,respectively.The temperature range checked is from 30 to 65℃.High yield of 81.53%with high se- lectivity of 91.84%can be obtained at higher temperature of 55℃when the residence time is 5.5min and the acet- aldehyde concentration is 9.85%（by mass）.And there is a critical acetaldehyde concentration point（Cccp）between 18%and 19.5%（by mass）.At temperature less than 55℃,the highest yield to peracetic acid at each temperature level increases with temperature when the acetaldehyde concentration is below Cccp and decreases with temperature when the acetaldehyde concentration is above Cccp.
基金supported by the fund of Natural Science Basic Research Program of Shaanxi(Grant No.2020JQ-190)National Natural Science Foundations of China(Grant Nos.51975480,52075449,and U1737205)China Postdoctoral Science Foundation funded project(Grant Nos.2019TQ0263,and 2020M683560)。
文摘This study focuses on the transient liquid phase(TLP)bonding of DD5 single-crystal superalloy to Cr Co Nibased medium-entropy alloy(MEA)using a BNi-2 filler alloy.The microstructure and mechanical properties of the TLP-bonded DD5/MEA joint were evaluated,and the microstructural evolution mechanism was investigated.The formation of the isothermal solidification zone(ISZ)depended on the diffusion of the melting-point depressants(Si and B elements)from the liquid filler into the DD5 and MEA substrates,as well as the dissolution of the substrates.Boron diffused along theγchannel of DD5 and reacted to form M_(5)B_(3)boride,herein referred to as the diffusion-affected zone(DAZ I).Similarly,the Cr_(5)B_(3)boride precipitated in the Ni-rich MEA matrix adjacent to the MEA substrate(i.e.,DAZ II).Additionally,a coherent orientation of[0]_(BCY)//[011]_(FCC)and(002)_(BCY)//(200)_(FCC)was detected between M_(5)B_(3)boride with a body-centered tetragonal(BCT)structure and the face-centered cubic(FCC)matrix.The performance of the joint was dominated by the properties of the bonding seam.As the bonding time increased from 20to 80 min,the athermal solidification zone(including eutectic microstructure)was gradually replaced by the ISZ exhibiting excellent plastic deformation capability,and the shear strength of the joint was improved.The maximum shear strength(752 MPa)was achieved when the eutectic-free joint was bonded at 1050℃ for 80 min.The fracture morphology revealed a mixture mode,indicating the initiation of cracks in the DAZ II,mainly propagating in the ISZ,and passing through the DAZ I.
