The effect of the rare earth cerium （Ce） on the hypereutectic Al-Si alloy under different casting states have been studied by optical microscope and quantitative image analysis. It is found that the size and the qua...The effect of the rare earth cerium （Ce） on the hypereutectic Al-Si alloy under different casting states have been studied by optical microscope and quantitative image analysis. It is found that the size and the quantity of primary silicon in castings decrease with the increase of added Ce in the melt. Meanwhile primary silicon changes from branched shape to fine facetted shape. Although the modification on eutectic silicon in castings also improves with the increase of added Ce in the melt, the effect of modification on eutectic silicon away from primary silicon is more obvious than that on eutectic silicon close to primary silicon. The modification mechanism was analyzed in detail by means of scanning electron microscope equipped with energy dispersive analysis of X-ray and thermodynamics analysis, which included the analysis on the change in standard Gibbs energy of reaction and reaction equilibrium.展开更多
A model of liquid ZA27 cast alloy is established according to molecular dynamics theory and an atomic structural model of co-existent a phase and liquid is also presented by means of computer programming. Recursion me...A model of liquid ZA27 cast alloy is established according to molecular dynamics theory and an atomic structural model of co-existent a phase and liquid is also presented by means of computer programming. Recursion method is adopted to calculate the electronic structure of RE (rare earth) in grains and around phase boundaries respectively. The calculation shows that RE is more stable around phase boundaries than in grains, which explains the fact that the solution of RE in a phase is less, and RE mainly aggregates in front of phase boundary. The calculations of bonding order integrals also show that RE in front of phases hardly solidify onto the grain surfaces as active element so as to prevent grains growth and refine the grains. As a result, the modification mechanism of RE may be explained from the view of electronic structure.展开更多
The model of the liquid-phase ZA27 alloys was set up by molecular dynamics theory. The atomic structure of phase, RE-compounds, and the phase-liquid interface in ZA27 alloys were constructed by computer programming. E...The model of the liquid-phase ZA27 alloys was set up by molecular dynamics theory. The atomic structure of phase, RE-compounds, and the phase-liquid interface in ZA27 alloys were constructed by computer programming. Electronic structures of phase with rare earth elements dissolved and of phase-liquid interfaces with rare earth elements enrichment in ZA27 casting alloys were investigated by using the Recursion method. The ESE energy of RE elements and the structure energy of RE-compounds, phase, and the liquid-phase ZA27 alloys were calculated. The results show that rare earth elements are more stable to be in the phase interface than in phase, which explains the fact of very small solid solubility of rare earth elements in phase, and the enrichment in the solid-liquid growth front. This makes dendrite melt and break down, dissociate and propagate. RE-compounds can act as heterogeneous nuclei for phase, leading to phase refinement. All above elucidates the modification mechanism of rare earth elements in zinc-aluminum casting alloys at electronic level.展开更多
In recent years,with the improvement of the requirements of road performance,modified emulsified asphalts with better performance has gradually replaced the emulsified asphalt and become the primary material for road ...In recent years,with the improvement of the requirements of road performance,modified emulsified asphalts with better performance has gradually replaced the emulsified asphalt and become the primary material for road maintenance.This paper introduces the modified emulsified asphalt materials commonly used in pavement maintenance projects,definitions and modified mechanisms of polymerized styrene butadiene rubber(SBR)modified emulsified asphalt,styrene butadiene styrene block polymer(SBS)modified emulsified asphalt and waterborne epoxy resin(WER)modified emulsified asphalt are summarized.The analysis focused on comparing the effects of modifiers,preparation process,auxiliary additives,and other factors on the performance of modified emulsified asphalt.In this paper,it is considered that the greatest impact on the performance of emulsified asphalt is the modifier,emulsifier mainly affects the speed of breaking the emulsion,stabilizers on the basic performance of emulsified asphalt evaporative residue is small;and when the modifier is distributed in the asphalt in a network,the dosage at this time is the recommended optimum dosage.Finally,this study recommends that in the future,the polymer-asphalt compatibility can be improved through composite modification,chemical grafting and other methods to continue to develop broader applicability and better performance of modified emulsified asphalt.展开更多
Modification conditions determine the surface topography and the active material phase composition of a catalyst.To study the influence of modification on a carbon-based sorbent,coconut husk activated carbon(AC)which ...Modification conditions determine the surface topography and the active material phase composition of a catalyst.To study the influence of modification on a carbon-based sorbent,coconut husk activated carbon(AC)which was activated using HNO_(3)and modified by FeSO4 and Fe(NO_(3))_(3)was examined.The pore textures and surface chemical characteristics of the carbon materials were examined by scanning electron microscopy(SEM),Brunner-Emmet-Teller(BET),X-ray diffraction(XRD)and Fourier transform infrared(FTIR)spectroscopy.The surface topography,the pore structure,active materials,and functional groups of AC,AC modificated by HNO3(HNO3/AC for short),and AC modificated by FeSO4 and Fe(NO3)3(Fe/AC for short)were systematically studied.Subsequently,the mechanism of modifying the conditions for the carbon materials was determined.Results showed that the surface micro topography of HNO3/AC became unsystematic and disordered.After modification with FeSO4,the ferriferous oxide was mainly present as a near-spherical crystal.Ferriferous oxides from Fe(NO_(3))_(3)modification mainly exhibited a plate shape.HNO_(3)modification could enlarge the pores but decrease the specific surface area of AC.FeSO_(4)modification resulted in a new net post structure in the pore canal of AC.Fe(NO_(3))_(3)modification caused the pore space structure to develop in the interior,and a higher calcination temperature was useful for ablation.The ash content of the AC was substantially reduced upon HNO_(3)modification.Upon FeSO_(4)modification,α-FeOOH,α-Fe_(2)O_(3)andγ-Fe_(2)O_(3)coexisted under the condition of a lower concentration of FeSO_(4)and a lower calcination temperature,and a higher FeSO_(4)concentration and calcination temperature generated moreα-Fe_(2)O_(3).The same Fe(NO_(3))_(3)modification and a higher calcination temperature were beneficial to the minor chipping formation ofγ-Fe_(2)O_(3).A higher Fe(NO_(3))_(3)loading produced a lower graphitization degree.HNO_(3)modification formed various new oxygen-containing functional groups and few nitrogen-containing groups.Based on the cover,FeSO_(4)and Fe(NO_(3))_(3)modification could decrease the oxygen-containing and nitrogen-containing functional groups.These results could optimize the modification condition and improve physical and chemical properties of carbon-based sorbents.展开更多
In order to reveal the surface modification mechanism of fine coal by electrochemical methods, the structural changes of the coal surface before and after electrochemical modification were investigated by Fourier Tran...In order to reveal the surface modification mechanism of fine coal by electrochemical methods, the structural changes of the coal surface before and after electrochemical modification were investigated by Fourier Transform In- frared Spectra (FTIR) and Raman Spectra. The results show that under certain electrochemical conditions, the oxy- gen-containing functional group in the coal structure and the oxygen content of absorption could be reduced and the floatability of coal improved. At the same time, the sulfur in the coal was reduced to the hydrophilic S2– which could be separated easily from coal. Thus electrochemical modification methods could be used to change the structure and func- tional group on the coal surface and to enhance the floatability of coal.展开更多
Steel slag(SS)accumulates unavoidably due to its complex and unstable composition,high production volumes,and limited value-added resource utilization.Single or multiple interface modifiers were proposed to enhance th...Steel slag(SS)accumulates unavoidably due to its complex and unstable composition,high production volumes,and limited value-added resource utilization.Single or multiple interface modifiers were proposed to enhance the properties of SS through high-speed dispersion,transforming its inherent hydrophilic and oleophobic characteristics into hydrophily and lipophilicity.The modification effects were innovatively assessed by observing the color changes of modified steel slag solutions following the dissolution-settlement equilibrium constant.This approach avoided human-induced errors and improved estimated accuracy in conformance with conventional methods such as oil absorption value,activation index,sedimentation volume,and lipophilicity.The hydrolysis of 3-aminopropyltriethoxysilane(KH)generated–Si(OH)_(3)structure to form hydrogen or covalent bonds with active substances(OH groups)from SS.Concurrently,SS underwent encapsulation via Si–O–Si structure resulting from the dehydration of–Si(OH)_(3).The stearic acid coupling agent(SA),aluminate coupling agent(AC),and titanate coupling agent(TN)underwent chemical reactions with Ca(OH)_(2),Al(OH)_(3),and CaCO_(3)in SS.The acidic SA primarily created stable chemical bonds and acted as a supplement due to its package,reducing surface activity and hydrophilicity while enhancing lipophilicity.Specifically,the optimal modification effect was obtained at 3 wt.%SA.Consequently,3 wt.%SA was established as the benchmark for multiple modifiers and the most effective combination was 3 wt.%SA and 3 wt.%AC.Compared with a single interface modifier,SA corroded the SS surface to provide numerous active sites for further modification by KH,AC,or TN,resulting in a more densely packed structure.In addition,more organic groups on SS prevent the proximity of other particles from agglomerating to achieve dispersion and a synergistic modification,laying a theoretical foundation of SS in a new pathway for organic composite materials.展开更多
Manganese oxides(MNO_(x)),as low-toxicity and high-abundance catalysts,have been demonstrated to hold great promise for application in advanced oxidation processes(AOPs).However,further application of this material is...Manganese oxides(MNO_(x)),as low-toxicity and high-abundance catalysts,have been demonstrated to hold great promise for application in advanced oxidation processes(AOPs).However,further application of this material is restricted due to its unsatisfactory oxidant activation efficiency.Fortunately,recently remarkable research on deep activation mechanisms and modification of MNO_(x)have been undertaken to improve its reactivity.Herein,modification enhancement mechanisms of MNO_(x)to efficiently degrade various organic contaminants were discussed and highlighted,including metal doping,coupling with other metal oxides,composite with carbonaceous material,and compounding with other support.The activation mechanisms of different MNO_(x)and derivative-modified material(such as doped MNO_(x),metal oxide-MNO_(x)hybrids,and MNO_(x)-carbonaceous material hybrids)were summarized in great details,which was specifically categorized into both radical and non-radical pathways.The effects of pH,inorganic ions,and natural organic matter on degradation reactions are also discussed.Finally,future research directions and perspectives are presented to provide a clear interpretation on the MNO_(x)initiated AOPs.展开更多
Calcium carbonate,which is widely employed as a filler added into the polymer matrix,has large numbers of applications owing to the excellent properties such as low cost,non-toxicity,high natural reserves and biocompa...Calcium carbonate,which is widely employed as a filler added into the polymer matrix,has large numbers of applications owing to the excellent properties such as low cost,non-toxicity,high natural reserves and biocompatibility.Nevertheless,in order to obtain the good filling effect,calcium carbonate needs to be surface modified by organic molecules so as to enhance the dispersion and compatibility within the composites.This review paper systematically introduces the theory,methods,and applications progress of calcium carbonate with surface modification.Additionally,the key factors that affect the properties of the composites as well as the current difficulties and challenges are highlighted.The current research progress and potential application prospects of calcium carbonate in the fields of plastics,rubber,paper,medicine and environmental protection are discussed as well.Generally,this review can provide valuable reference for the modification and comprehensive utilization of calcium carbonate.展开更多
Loess disintegration can lead to geotechnical engineering problems,e.g.,slope erosion,wetting-induced landslide,and hydroconsolidation.Microbially induced calcite precipitation(MICP)technique is a potential loess rein...Loess disintegration can lead to geotechnical engineering problems,e.g.,slope erosion,wetting-induced landslide,and hydroconsolidation.Microbially induced calcite precipitation(MICP)technique is a potential loess reinforcing method.This study investigated the physical-mechanical properties of MICP-treated loess and then explored the mechanism of loess modification by MICP.Here,loess first underwent MICP treatment,i.e.,mixing loess with Sporosarcina pasteurii and cementation solution(CS).Then,the effects of the CS concentration(0.2,0.6,0.8,and 1 M)on the physical and mechanical properties of the MICP-treated loess were tested.Finally,the static contact angle test,scanning electron microscopy(SEM),and X-ray diffractometry(XRD)were conducted to study the mechanism of MICP treatment on loess.Results showed the following property changes of loess after MICP treatment:the liquid limit decreased by 1.7%,the average particle size increased from 6 to 47μm,the specific gravity decreased from 2.65 to 2.43,the unconfined compressive strength increased from 37 to 71 k Pa,and the disintegration time increased from 10 to 25 min.Besides,the shear strength also increased,and the shear strength parameters(cohesion c and internal friction angle?)varied with the CS concentration.The static contact angle tests indicated that the water absorption ability of loess was reduced after MICP treatment.SEM and XRD results verified that the CaCO_(3)from MICP was attributed to the above results.The above findings explained the mechanism of MICP treatment of loess:the CaCO_(3)coats and cements the particles,and fills the pores of loess,improving the strength and water stability of loess.展开更多
To study the mechanism by which activated carbon is modified by HNO3 and Mn(NO3)2,the pore texture and surface chemical characteristics of carbon materials in coconut husk activated carbon(AC)were examined via scannin...To study the mechanism by which activated carbon is modified by HNO3 and Mn(NO3)2,the pore texture and surface chemical characteristics of carbon materials in coconut husk activated carbon(AC)were examined via scanning electron microscopy(SEM),Brunauer-Emmett-Teller(BET),X-ray diffraction(XRD),Fourier-transform infrared spectroscopy(FTIR),and X-ray photoelectron spectroscopy(XPS).After being modified by HNO3,the millipore character of AC became deformed,and the character of the adjacent pores remained consolidated.The surface manganites of Mn/AC-1 presented as block and reticular fiber structures,Mn/AC-2's surface manganites presented as petty mammock crystals,and Mn/AC-3's surface manganites were observed as gauze nanosheets that interlace to fill in the pore canal.Nitric acid modification was shown to enlarge surface pores but decrease the specific surface area of AC.Mn loading can be used to construct a new pore structure that,in turn,increased the total specific surface area as well as the specific surface area and the volume of the millipores.Mn/AC-2's pore structure was optimized at a calcination temperature of 500℃and a loading quantity of 5%.The ash content of AC was considerably reduced after modified by HNO3.The active materials for Mn/AC-1 mainly consisted of Mn3O4,with a few Mn2O3 crystals,whereas Mn/AC-2's materials were mainly Mn3O4 and some MnO crystals.Mn/AC-3 was exclusively composed of Mn3O4.HNO3 activation and Mn loading modification did not considerably affect the functional group species present on the catalyst.Modification conditions using the same loading quantities and higher calcination temperatures decreased the number of O—H and N—H bonds while conversely increasing the number of CC and C—O bonds.On the contrary,the use of a higher loading quantity while maintaining the same calcination temperature increased the number of O—H and N—H bonds.A higher loading quantity is beneficial for increasing Mn^4+species.A higher calcination temperature is beneficial for increasing Mn^3+species.The results can optimize the conditions under which Mn/AC catalyst modification occurs,thus improving the physical and chemical properties of carbon-based sorbents.展开更多
With the rapid development of asphalt pavement technology,it has attracted considerable attention to improving the durability of asphalt pavement.An effective action is to use modified asphalt with high performance an...With the rapid development of asphalt pavement technology,it has attracted considerable attention to improving the durability of asphalt pavement.An effective action is to use modified asphalt with high performance and durability.Polyurethane(PU)has been used in asphalt pavement engineering to enhance the durability and service life of asphalt pavement because of its excellent high-temperature performance,toughness,wear resistance,aging resistance and oil resistance.However,PU modified asphalt technology is still in the exploratory stage.The preparation,modification mechanism and working performances of PU modified asphalt need to be further clarified.Therefore,this paper summarized the research progress of PU modified asphalt and its mixture.The composition of PU modified asphalt was introduced.The addition methods of PU materials and preparation process parameters of the PU modified asphalt were determined.The modification mechanism of PU on asphalt was discussed.The effects of polyurethane on asphalt were analyzed and the road performances of its mixture were evaluated.Finally,the development tendency towards PU modified asphalt and its mixture were forecasted.展开更多
Dysprosium composite cobalt ferrite ionic magnetic fluids were prepared by precipitation in the presence of Tri-sodium citrate. Influence of dysprosium modification on magnetic property is studied. The result shows th...Dysprosium composite cobalt ferrite ionic magnetic fluids were prepared by precipitation in the presence of Tri-sodium citrate. Influence of dysprosium modification on magnetic property is studied. The result shows that magnetic response toward exterior magnetic field can be improved by adding Dy3+. Studies also show that the increase of reaction temperature may improve the modification effect of dysprosium. By adding dysprosium ions, the average diameter of the magnetic nanoparticles will be decreased evidently. It is clear that the particles appear as balls. Cobalt ferrite with sizes of 12-15 nm, rare earth composite cobalt ferrite with sizes of 6-8 nm.展开更多
Ni-rich cathode materials,exemplified by LiNi_(1-x-y)Co_(x)MnyO_(2)(NCM),have significantly propelled Li-ion battery(LIB)technology forward owing to their high energy density.However,the long-term storage stability of...Ni-rich cathode materials,exemplified by LiNi_(1-x-y)Co_(x)MnyO_(2)(NCM),have significantly propelled Li-ion battery(LIB)technology forward owing to their high energy density.However,the long-term storage stability of these materials remains a critical challenge that must be addressed.This review provides a comprehensive analysis of the storage failure mechanisms in both polycrystalline(PC-NCM)and single crystal(SC-NCM)forms,a topic that has been seldom reviewed.It delves into the microstructural changes and performance degradation that occur during storage,emphasizing the effects of environmental factors on NCM materials,including the formation of surface impurities and structural deterioration.Additionally,the review discusses various enhancement strategies,such as surface coatings,doping,and gas treatments,which are designed to improve storage stability.Furthermore,the review projects insights from current polycrystalline studies to suggest future research directions aimed at enhancing the air stability of SC-NCM,which is vital for improving the safety and durability of LIBs.展开更多
In order to investigate the influening factors of organic modification procedure and find out connections between organic modification and the properties of bentonite greases, organic montmorillonite(OMMT) thickeners ...In order to investigate the influening factors of organic modification procedure and find out connections between organic modification and the properties of bentonite greases, organic montmorillonite(OMMT) thickeners with different surfactant dosages and constituents were synthesized through intercalation reaction between sodium montmorillonite(NaM MT) and quaternary ammonium surfactants in aqueous solvents. The lubricating greases were prepared with the resulting organoclays, while the penetration and oil separation of lubricating greases were evaluated, respectively. The surface modification process of montmorillonite(MMT) was analyzed and the thickening mechanism of OMMT was discussed in this study. The experimental results showed that, with an increasing amount of surfactant, the basal spacing between the clay platelets was increasing and the structure of modifier molecules layer in the interlayer was changing from lateral bilayer to paraffin-type bilayer. The optimal properties of lubricating greases were achieved, when the structure of surfactant molecules loaded in the interlayer was the paraffin-type monolayer, which meant that the dosage of modifier was equal to 120—140 mmol/(100g). Meanwhile, it was found that the thickening performance, colloid stability, anti-wear and friction-reducing performance of lubricating greases were improved, when the surfactants were mixed with octadecyl trimethyl ammonium chloride(OTAC) and hexadecyl trimethyl ammonium chloride(HTAC). And the optimum mole ratio of two surfactants is was 1:1.展开更多
To expand the application of polyurethane(PU)modified bitumen,it is necessary to understand the influence of PU raw materials on PU modified bitumen systematically.Three polyether-based polyurethanes were used to modi...To expand the application of polyurethane(PU)modified bitumen,it is necessary to understand the influence of PU raw materials on PU modified bitumen systematically.Three polyether-based polyurethanes were used to modify the unmodified bitumen,synthesised from toluene diisocyanate(TDI),diphenylmethane diisocyanate(MDI),and polyaryl polyisocyanate(PAPI)by reaction with polytetrahydrofuran diol(PTMEG)respectively.And the performance of polyether-based PU modified bitumen was investigated at various contents of isocyanates.Firstly,the modification mechanism of PU modified bitumen binders was analysed by Fourier transform infrared spectroscopy(FTIR).Then,the high and low temperature properties and resistance to permanent deformation of modified bitumen binders were investigated through dynamic shear rheometer(DSR)test,bending beam rheometer(BBR)test and multiple stress creep recovery(MSCR)test.Finally,the microstructure and molecular movement were analyzed by fluorescence microscopy(FM),atomic force microscopy(AFM)and differential scanning calorimetry(DSC).As the results show,there are significant differences in the molecular structure,cross-linking and hydrogen bonding of polyurethane modifiers synthesised from different isocyanates,which then affect the interaction between polyurethane molecules and bitumen molecules and result in different modification effects on bitumen.Concerning high-temperature properties and storage stability,PU synthesised by PAPI is the best solution for improving bitumen.PU synthesised by TDI offers the best improvement in low temperature performance.It is worth noting that the PU synthesised by MDI provides a more balanced improvement in high and low temperature performances.This study provides guidance for the development of PU modified bitumen.展开更多
Femtosecond pulsed lasers offer significant advantages for micro-/nano-modifications in integrated photonics.Microring resonators(MRRs),which are essential components in photonic integrated circuits(PICs),are widely e...Femtosecond pulsed lasers offer significant advantages for micro-/nano-modifications in integrated photonics.Microring resonators(MRRs),which are essential components in photonic integrated circuits(PICs),are widely employed in various fields,including optical communication,sensing,and filtering.In this study,we investigate the modification mechanisms associated with femtosecond laser interactions with MRRs fabricated on a lowpressure chemical vapor deposition(LPCVD)-silicon nitride(SiN)photonic platform,with emphasis on the post-fabrication trimming of second-order microring filters and MRR-based four-channel wavelength-division multiplexing(WDM).We examine 10 MRRs located at different positions on a wafer and discovered resonance wavelength shifts exceeding 1 nm due to fabrication-induced variations.Interactions between femtosecond lasers and LPCVD-SiN films resulted in silicon nanoclusters,which significantly redshifted the resonance wavelength of the MRRs.Additionally,the extinction ratio of MRRs improved by over 11.8 dB within the conventional band after laser modification.This technique is employed to enhance the performance of second-order MRRs and the four-channel WDM configuration,thus providing critical experimental evidence for leveraging femtosecond lasers to optimize LPCVD-SiN PICs.展开更多
A near eutectic Al−12.6Si alloy was developed with 0.0wt%,2.0wt%,4.0wt%,and 6.0wt%Al−5Ti−1B master alloy.The micro-structural morphology,hardness,tensile strength,elongation,and fracture behaviour of the alloys were s...A near eutectic Al−12.6Si alloy was developed with 0.0wt%,2.0wt%,4.0wt%,and 6.0wt%Al−5Ti−1B master alloy.The micro-structural morphology,hardness,tensile strength,elongation,and fracture behaviour of the alloys were studied.The unmodified Al−12.6Si al-loy has an irregular needle and plate-like eutectic silicon(ESi)and coarse polygonal primary silicon(PSi)particles in the matrix-likeα-Al phase.The P_(Si),E_(Si),andα-Al morphology and volume fraction were changed due to the addition of the Al−5Ti−1B master alloy.The hardness,UTS,and elongation improved due to the microstructural modification.Nano-sized in-situ Al3Ti particles and ex-situ TiB_(2)particles caused the mi-crostructural modification.The fracture images of the developed alloys exhibit a ductile and brittle mode of fracture at the same time.The Al−5Ti−1B modified alloys have a more ductile mode of fracture and more dimples compared to the unmodified alloy.展开更多
Fe-loaded activated carbon(AC)has high surface acidity and more active sites,while manganese-loaded AC has high oxygen content.Coconut husk AC modified by Fe-Mn was studied with the aim of revealing the modification m...Fe-loaded activated carbon(AC)has high surface acidity and more active sites,while manganese-loaded AC has high oxygen content.Coconut husk AC modified by Fe-Mn was studied with the aim of revealing the modification mechanism.First,HNO_(3)AC was prepared using the nitric acid immersion method.Second,Fe-Mn/AC was prepared using the Fe(N0_(3))_(3)and Mn(N0_(3))_(2)sequential immersion.The effects of HNO_(3),Fe(N0_(3))_(3),and Mn(N0_(3))_(2)on the pore texture and surface chemical characteristics of carbon materials were examined by scanning electron microscopy,Brunauer-Emmett-Teller(BET)analysis,X-ray diffraction and Fourier-transform infrared spectroscopy.The surface topography,pore structure,active material,and functional groups of AC,HNO_(3)/AC,and Fe-Mn/AC were systematically studied.The following results were obtained.The surface of HNO_(3)AC has more ditches and air voids;the micropores of HNO_(3)AC are deformed and flattened compared to those of AC.The surface of Fe-Mn/AC exhibits an accumulation phenomenon.MnFe_(2)O_(4)and FeMn_(2)O_(4)formed more pore structures.AC and HNO_(3)AC have numerous micropores.The higher loading quantity of Fe-Mn results in bigger specific surface.The active components of Fe-Mn/AC-1,Fe-Mn/AC-2,Fe-Mn/AC-3,and Fe-Mn/AC-4 are MnFe_(2)O_(4),MnO_(0.43)Fe_(2.57)O_(4),Mn_(3)O_(4),and ot-Fe_(2)O_(3)>respectively.The surface functional groups of AC and HNO_(3)AC are oxygen-containing functional groups.The effect of Fe-Mn modifying conditions on functional group species is rare;however,Fe/AC has more oxygen-containing functional groups.These research findings can aid in the desulfurization and denitrification of the Fe-Mn/AC catalyst.展开更多
A calcium sulfate whisker （CSW） coated with glutaraldehyde crosslinked chitosan （GACS） was prepared to reinforce polyvinyl chloride （PVC） in this study. The results show that the optimum concentration of both ch...A calcium sulfate whisker （CSW） coated with glutaraldehyde crosslinked chitosan （GACS） was prepared to reinforce polyvinyl chloride （PVC） in this study. The results show that the optimum concentration of both chitosan （CS） and glutaraldehyde （GA） is 0.05 wt%. The tensile strength, impact strength, flexural modulus and vicat softening temperature of the PVC composite with 12 wt% of modified CSW are in- creased by 1 Z5%, 40.4%, 0.8% and 3.8% compared with those of the PVC composite with 12 wt~ of unmodified CSW, and by 2.9%, 42.4%, 2Z1% and 6.8% compared with those of pure PVC, respectively. The dynamic mechanical analysis results indicate that the modified CSW/PVC composite exhibits much higher storage modulus and glass transition temperature than those of unmodified CSW/PVC composite and pure PVC. In addition, the modified CSW/PVC composite also demonstrates good thermal properties with a high rapidest decomposition temperature （Trvd） and char residue. The scanning electron microscopy images of tensile-fractured surfaces show that the modified CSW has a strong interfacial adhesion with PVC matrix.展开更多
基金The work is financially supported by Shanghai Leading Academic Discipline Project (No. T0101)the Open Funds of Shanghai Key Laboratory of Metal Function Materials Research and Application.
文摘The effect of the rare earth cerium （Ce） on the hypereutectic Al-Si alloy under different casting states have been studied by optical microscope and quantitative image analysis. It is found that the size and the quantity of primary silicon in castings decrease with the increase of added Ce in the melt. Meanwhile primary silicon changes from branched shape to fine facetted shape. Although the modification on eutectic silicon in castings also improves with the increase of added Ce in the melt, the effect of modification on eutectic silicon away from primary silicon is more obvious than that on eutectic silicon close to primary silicon. The modification mechanism was analyzed in detail by means of scanning electron microscope equipped with energy dispersive analysis of X-ray and thermodynamics analysis, which included the analysis on the change in standard Gibbs energy of reaction and reaction equilibrium.
基金Authors deeply appreciate the support from the National Natural Science Foundation of China(No.50275098)the Natural Science Foundation of Liaoning Province(No.20022031)
文摘A model of liquid ZA27 cast alloy is established according to molecular dynamics theory and an atomic structural model of co-existent a phase and liquid is also presented by means of computer programming. Recursion method is adopted to calculate the electronic structure of RE (rare earth) in grains and around phase boundaries respectively. The calculation shows that RE is more stable around phase boundaries than in grains, which explains the fact that the solution of RE in a phase is less, and RE mainly aggregates in front of phase boundary. The calculations of bonding order integrals also show that RE in front of phases hardly solidify onto the grain surfaces as active element so as to prevent grains growth and refine the grains. As a result, the modification mechanism of RE may be explained from the view of electronic structure.
文摘The model of the liquid-phase ZA27 alloys was set up by molecular dynamics theory. The atomic structure of phase, RE-compounds, and the phase-liquid interface in ZA27 alloys were constructed by computer programming. Electronic structures of phase with rare earth elements dissolved and of phase-liquid interfaces with rare earth elements enrichment in ZA27 casting alloys were investigated by using the Recursion method. The ESE energy of RE elements and the structure energy of RE-compounds, phase, and the liquid-phase ZA27 alloys were calculated. The results show that rare earth elements are more stable to be in the phase interface than in phase, which explains the fact of very small solid solubility of rare earth elements in phase, and the enrichment in the solid-liquid growth front. This makes dendrite melt and break down, dissociate and propagate. RE-compounds can act as heterogeneous nuclei for phase, leading to phase refinement. All above elucidates the modification mechanism of rare earth elements in zinc-aluminum casting alloys at electronic level.
基金The authors acknowledge the financial support from National Natural Science Foundation of China(No.51968006).
文摘In recent years,with the improvement of the requirements of road performance,modified emulsified asphalts with better performance has gradually replaced the emulsified asphalt and become the primary material for road maintenance.This paper introduces the modified emulsified asphalt materials commonly used in pavement maintenance projects,definitions and modified mechanisms of polymerized styrene butadiene rubber(SBR)modified emulsified asphalt,styrene butadiene styrene block polymer(SBS)modified emulsified asphalt and waterborne epoxy resin(WER)modified emulsified asphalt are summarized.The analysis focused on comparing the effects of modifiers,preparation process,auxiliary additives,and other factors on the performance of modified emulsified asphalt.In this paper,it is considered that the greatest impact on the performance of emulsified asphalt is the modifier,emulsifier mainly affects the speed of breaking the emulsion,stabilizers on the basic performance of emulsified asphalt evaporative residue is small;and when the modifier is distributed in the asphalt in a network,the dosage at this time is the recommended optimum dosage.Finally,this study recommends that in the future,the polymer-asphalt compatibility can be improved through composite modification,chemical grafting and other methods to continue to develop broader applicability and better performance of modified emulsified asphalt.
基金General Project of Science and Technology Plan of Yunnan Science and Technology Department,China(No.2019FB077)Open Fund of Key Laboratory of Ministry of Education for Metallurgical Emission Reduction and Comprehensive Utilization of Resources,China(No.JKF19-08)。
文摘Modification conditions determine the surface topography and the active material phase composition of a catalyst.To study the influence of modification on a carbon-based sorbent,coconut husk activated carbon(AC)which was activated using HNO_(3)and modified by FeSO4 and Fe(NO_(3))_(3)was examined.The pore textures and surface chemical characteristics of the carbon materials were examined by scanning electron microscopy(SEM),Brunner-Emmet-Teller(BET),X-ray diffraction(XRD)and Fourier transform infrared(FTIR)spectroscopy.The surface topography,the pore structure,active materials,and functional groups of AC,AC modificated by HNO3(HNO3/AC for short),and AC modificated by FeSO4 and Fe(NO3)3(Fe/AC for short)were systematically studied.Subsequently,the mechanism of modifying the conditions for the carbon materials was determined.Results showed that the surface micro topography of HNO3/AC became unsystematic and disordered.After modification with FeSO4,the ferriferous oxide was mainly present as a near-spherical crystal.Ferriferous oxides from Fe(NO_(3))_(3)modification mainly exhibited a plate shape.HNO_(3)modification could enlarge the pores but decrease the specific surface area of AC.FeSO_(4)modification resulted in a new net post structure in the pore canal of AC.Fe(NO_(3))_(3)modification caused the pore space structure to develop in the interior,and a higher calcination temperature was useful for ablation.The ash content of the AC was substantially reduced upon HNO_(3)modification.Upon FeSO_(4)modification,α-FeOOH,α-Fe_(2)O_(3)andγ-Fe_(2)O_(3)coexisted under the condition of a lower concentration of FeSO_(4)and a lower calcination temperature,and a higher FeSO_(4)concentration and calcination temperature generated moreα-Fe_(2)O_(3).The same Fe(NO_(3))_(3)modification and a higher calcination temperature were beneficial to the minor chipping formation ofγ-Fe_(2)O_(3).A higher Fe(NO_(3))_(3)loading produced a lower graphitization degree.HNO_(3)modification formed various new oxygen-containing functional groups and few nitrogen-containing groups.Based on the cover,FeSO_(4)and Fe(NO_(3))_(3)modification could decrease the oxygen-containing and nitrogen-containing functional groups.These results could optimize the modification condition and improve physical and chemical properties of carbon-based sorbents.
基金Project 50174054 supported by the National Natural Science Foundation of China
文摘In order to reveal the surface modification mechanism of fine coal by electrochemical methods, the structural changes of the coal surface before and after electrochemical modification were investigated by Fourier Transform In- frared Spectra (FTIR) and Raman Spectra. The results show that under certain electrochemical conditions, the oxy- gen-containing functional group in the coal structure and the oxygen content of absorption could be reduced and the floatability of coal improved. At the same time, the sulfur in the coal was reduced to the hydrophilic S2– which could be separated easily from coal. Thus electrochemical modification methods could be used to change the structure and func- tional group on the coal surface and to enhance the floatability of coal.
基金supported by the National Natural Science Foundation of China(U23A20605)Anhui Graduate Innovation and Entrepreneurship Practice Project(2022cxcysj090)+2 种基金China Baowu Low Carbon Metallurgy Innovation Foundation(BWLCF202202)the University Synergy Innovation Program of Anhui Province(GXXT-2020-072)the Outstanding Youth Fund of Anhui Province(2208085J19).
文摘Steel slag(SS)accumulates unavoidably due to its complex and unstable composition,high production volumes,and limited value-added resource utilization.Single or multiple interface modifiers were proposed to enhance the properties of SS through high-speed dispersion,transforming its inherent hydrophilic and oleophobic characteristics into hydrophily and lipophilicity.The modification effects were innovatively assessed by observing the color changes of modified steel slag solutions following the dissolution-settlement equilibrium constant.This approach avoided human-induced errors and improved estimated accuracy in conformance with conventional methods such as oil absorption value,activation index,sedimentation volume,and lipophilicity.The hydrolysis of 3-aminopropyltriethoxysilane(KH)generated–Si(OH)_(3)structure to form hydrogen or covalent bonds with active substances(OH groups)from SS.Concurrently,SS underwent encapsulation via Si–O–Si structure resulting from the dehydration of–Si(OH)_(3).The stearic acid coupling agent(SA),aluminate coupling agent(AC),and titanate coupling agent(TN)underwent chemical reactions with Ca(OH)_(2),Al(OH)_(3),and CaCO_(3)in SS.The acidic SA primarily created stable chemical bonds and acted as a supplement due to its package,reducing surface activity and hydrophilicity while enhancing lipophilicity.Specifically,the optimal modification effect was obtained at 3 wt.%SA.Consequently,3 wt.%SA was established as the benchmark for multiple modifiers and the most effective combination was 3 wt.%SA and 3 wt.%AC.Compared with a single interface modifier,SA corroded the SS surface to provide numerous active sites for further modification by KH,AC,or TN,resulting in a more densely packed structure.In addition,more organic groups on SS prevent the proximity of other particles from agglomerating to achieve dispersion and a synergistic modification,laying a theoretical foundation of SS in a new pathway for organic composite materials.
基金the National Natural Science Foundation of China(Nos.52170088 and 52070133)for financial support。
文摘Manganese oxides(MNO_(x)),as low-toxicity and high-abundance catalysts,have been demonstrated to hold great promise for application in advanced oxidation processes(AOPs).However,further application of this material is restricted due to its unsatisfactory oxidant activation efficiency.Fortunately,recently remarkable research on deep activation mechanisms and modification of MNO_(x)have been undertaken to improve its reactivity.Herein,modification enhancement mechanisms of MNO_(x)to efficiently degrade various organic contaminants were discussed and highlighted,including metal doping,coupling with other metal oxides,composite with carbonaceous material,and compounding with other support.The activation mechanisms of different MNO_(x)and derivative-modified material(such as doped MNO_(x),metal oxide-MNO_(x)hybrids,and MNO_(x)-carbonaceous material hybrids)were summarized in great details,which was specifically categorized into both radical and non-radical pathways.The effects of pH,inorganic ions,and natural organic matter on degradation reactions are also discussed.Finally,future research directions and perspectives are presented to provide a clear interpretation on the MNO_(x)initiated AOPs.
基金Project(AA18242008)supported by the Guangxi Science&Technology Major Project,ChinaProject(HZXYKFKT201904)supported by the Opening Project of Guangxi Key Laboratory of Calcium Carbonate Resources Comprehensive Utilization,China。
文摘Calcium carbonate,which is widely employed as a filler added into the polymer matrix,has large numbers of applications owing to the excellent properties such as low cost,non-toxicity,high natural reserves and biocompatibility.Nevertheless,in order to obtain the good filling effect,calcium carbonate needs to be surface modified by organic molecules so as to enhance the dispersion and compatibility within the composites.This review paper systematically introduces the theory,methods,and applications progress of calcium carbonate with surface modification.Additionally,the key factors that affect the properties of the composites as well as the current difficulties and challenges are highlighted.The current research progress and potential application prospects of calcium carbonate in the fields of plastics,rubber,paper,medicine and environmental protection are discussed as well.Generally,this review can provide valuable reference for the modification and comprehensive utilization of calcium carbonate.
基金funded by the Beijing Natural Science Foundation(No.8214060)the National Natural Science Foundation of China(No.42107164)the 2021 Graduate Innovation Fund Project of China University of Geosciences,Beijing(No.ZD2021YC059)。
文摘Loess disintegration can lead to geotechnical engineering problems,e.g.,slope erosion,wetting-induced landslide,and hydroconsolidation.Microbially induced calcite precipitation(MICP)technique is a potential loess reinforcing method.This study investigated the physical-mechanical properties of MICP-treated loess and then explored the mechanism of loess modification by MICP.Here,loess first underwent MICP treatment,i.e.,mixing loess with Sporosarcina pasteurii and cementation solution(CS).Then,the effects of the CS concentration(0.2,0.6,0.8,and 1 M)on the physical and mechanical properties of the MICP-treated loess were tested.Finally,the static contact angle test,scanning electron microscopy(SEM),and X-ray diffractometry(XRD)were conducted to study the mechanism of MICP treatment on loess.Results showed the following property changes of loess after MICP treatment:the liquid limit decreased by 1.7%,the average particle size increased from 6 to 47μm,the specific gravity decreased from 2.65 to 2.43,the unconfined compressive strength increased from 37 to 71 k Pa,and the disintegration time increased from 10 to 25 min.Besides,the shear strength also increased,and the shear strength parameters(cohesion c and internal friction angle?)varied with the CS concentration.The static contact angle tests indicated that the water absorption ability of loess was reduced after MICP treatment.SEM and XRD results verified that the CaCO_(3)from MICP was attributed to the above results.The above findings explained the mechanism of MICP treatment of loess:the CaCO_(3)coats and cements the particles,and fills the pores of loess,improving the strength and water stability of loess.
基金The Science and Technology Plan of Yunnan Science and Technology Department(No.2019FB077,202001AT070029)the Open Fund of Key Laboratory of Ministry of Education for Metallurgical Emission Reduction and Comprehensive Utilization of Resources(No.JKF19-08)the Industrialization Cultivation Project of Scientific Research Fund of Yunnan Provincial Department of Education(No.2016CYH07).
文摘To study the mechanism by which activated carbon is modified by HNO3 and Mn(NO3)2,the pore texture and surface chemical characteristics of carbon materials in coconut husk activated carbon(AC)were examined via scanning electron microscopy(SEM),Brunauer-Emmett-Teller(BET),X-ray diffraction(XRD),Fourier-transform infrared spectroscopy(FTIR),and X-ray photoelectron spectroscopy(XPS).After being modified by HNO3,the millipore character of AC became deformed,and the character of the adjacent pores remained consolidated.The surface manganites of Mn/AC-1 presented as block and reticular fiber structures,Mn/AC-2's surface manganites presented as petty mammock crystals,and Mn/AC-3's surface manganites were observed as gauze nanosheets that interlace to fill in the pore canal.Nitric acid modification was shown to enlarge surface pores but decrease the specific surface area of AC.Mn loading can be used to construct a new pore structure that,in turn,increased the total specific surface area as well as the specific surface area and the volume of the millipores.Mn/AC-2's pore structure was optimized at a calcination temperature of 500℃and a loading quantity of 5%.The ash content of AC was considerably reduced after modified by HNO3.The active materials for Mn/AC-1 mainly consisted of Mn3O4,with a few Mn2O3 crystals,whereas Mn/AC-2's materials were mainly Mn3O4 and some MnO crystals.Mn/AC-3 was exclusively composed of Mn3O4.HNO3 activation and Mn loading modification did not considerably affect the functional group species present on the catalyst.Modification conditions using the same loading quantities and higher calcination temperatures decreased the number of O—H and N—H bonds while conversely increasing the number of CC and C—O bonds.On the contrary,the use of a higher loading quantity while maintaining the same calcination temperature increased the number of O—H and N—H bonds.A higher loading quantity is beneficial for increasing Mn^4+species.A higher calcination temperature is beneficial for increasing Mn^3+species.The results can optimize the conditions under which Mn/AC catalyst modification occurs,thus improving the physical and chemical properties of carbon-based sorbents.
基金supported by Innovation Capability Support Program of Shaanxi(2022TD-07).
文摘With the rapid development of asphalt pavement technology,it has attracted considerable attention to improving the durability of asphalt pavement.An effective action is to use modified asphalt with high performance and durability.Polyurethane(PU)has been used in asphalt pavement engineering to enhance the durability and service life of asphalt pavement because of its excellent high-temperature performance,toughness,wear resistance,aging resistance and oil resistance.However,PU modified asphalt technology is still in the exploratory stage.The preparation,modification mechanism and working performances of PU modified asphalt need to be further clarified.Therefore,this paper summarized the research progress of PU modified asphalt and its mixture.The composition of PU modified asphalt was introduced.The addition methods of PU materials and preparation process parameters of the PU modified asphalt were determined.The modification mechanism of PU on asphalt was discussed.The effects of polyurethane on asphalt were analyzed and the road performances of its mixture were evaluated.Finally,the development tendency towards PU modified asphalt and its mixture were forecasted.
文摘Dysprosium composite cobalt ferrite ionic magnetic fluids were prepared by precipitation in the presence of Tri-sodium citrate. Influence of dysprosium modification on magnetic property is studied. The result shows that magnetic response toward exterior magnetic field can be improved by adding Dy3+. Studies also show that the increase of reaction temperature may improve the modification effect of dysprosium. By adding dysprosium ions, the average diameter of the magnetic nanoparticles will be decreased evidently. It is clear that the particles appear as balls. Cobalt ferrite with sizes of 12-15 nm, rare earth composite cobalt ferrite with sizes of 6-8 nm.
基金sponsored by the National Natural Science Foundation of China(Grant No.22109010)Beijing Nova Program,Chongqing Outstanding Youth Fund(Grant No.2022NSCQ-JQX3895)National Key R&D Program of China(Grant No.2021YFC2902905).
文摘Ni-rich cathode materials,exemplified by LiNi_(1-x-y)Co_(x)MnyO_(2)(NCM),have significantly propelled Li-ion battery(LIB)technology forward owing to their high energy density.However,the long-term storage stability of these materials remains a critical challenge that must be addressed.This review provides a comprehensive analysis of the storage failure mechanisms in both polycrystalline(PC-NCM)and single crystal(SC-NCM)forms,a topic that has been seldom reviewed.It delves into the microstructural changes and performance degradation that occur during storage,emphasizing the effects of environmental factors on NCM materials,including the formation of surface impurities and structural deterioration.Additionally,the review discusses various enhancement strategies,such as surface coatings,doping,and gas treatments,which are designed to improve storage stability.Furthermore,the review projects insights from current polycrystalline studies to suggest future research directions aimed at enhancing the air stability of SC-NCM,which is vital for improving the safety and durability of LIBs.
基金financially supported by the Chongqing Construction Project of Innovation Teams in Colleges and Universities-Petroleum Products Application Engineering and Technology(Project No.KJTD201342)the Chongqing Project of Innovation Research by Postgraduates(Project No.CYB16130)
文摘In order to investigate the influening factors of organic modification procedure and find out connections between organic modification and the properties of bentonite greases, organic montmorillonite(OMMT) thickeners with different surfactant dosages and constituents were synthesized through intercalation reaction between sodium montmorillonite(NaM MT) and quaternary ammonium surfactants in aqueous solvents. The lubricating greases were prepared with the resulting organoclays, while the penetration and oil separation of lubricating greases were evaluated, respectively. The surface modification process of montmorillonite(MMT) was analyzed and the thickening mechanism of OMMT was discussed in this study. The experimental results showed that, with an increasing amount of surfactant, the basal spacing between the clay platelets was increasing and the structure of modifier molecules layer in the interlayer was changing from lateral bilayer to paraffin-type bilayer. The optimal properties of lubricating greases were achieved, when the structure of surfactant molecules loaded in the interlayer was the paraffin-type monolayer, which meant that the dosage of modifier was equal to 120—140 mmol/(100g). Meanwhile, it was found that the thickening performance, colloid stability, anti-wear and friction-reducing performance of lubricating greases were improved, when the surfactants were mixed with octadecyl trimethyl ammonium chloride(OTAC) and hexadecyl trimethyl ammonium chloride(HTAC). And the optimum mole ratio of two surfactants is was 1:1.
基金supported by the fund of Key R&D Project in Shaanxi Province(No.2024GX-YBXM-371)the Shaanxi Provincial Communication Construction Group(No.17-06K)the fund of Beijing Key Laboratory of Quality Evaluation Technology for Hygiene and Safety of Plastics,Beijing Technology and Business University(QETHSP2020003)。
文摘To expand the application of polyurethane(PU)modified bitumen,it is necessary to understand the influence of PU raw materials on PU modified bitumen systematically.Three polyether-based polyurethanes were used to modify the unmodified bitumen,synthesised from toluene diisocyanate(TDI),diphenylmethane diisocyanate(MDI),and polyaryl polyisocyanate(PAPI)by reaction with polytetrahydrofuran diol(PTMEG)respectively.And the performance of polyether-based PU modified bitumen was investigated at various contents of isocyanates.Firstly,the modification mechanism of PU modified bitumen binders was analysed by Fourier transform infrared spectroscopy(FTIR).Then,the high and low temperature properties and resistance to permanent deformation of modified bitumen binders were investigated through dynamic shear rheometer(DSR)test,bending beam rheometer(BBR)test and multiple stress creep recovery(MSCR)test.Finally,the microstructure and molecular movement were analyzed by fluorescence microscopy(FM),atomic force microscopy(AFM)and differential scanning calorimetry(DSC).As the results show,there are significant differences in the molecular structure,cross-linking and hydrogen bonding of polyurethane modifiers synthesised from different isocyanates,which then affect the interaction between polyurethane molecules and bitumen molecules and result in different modification effects on bitumen.Concerning high-temperature properties and storage stability,PU synthesised by PAPI is the best solution for improving bitumen.PU synthesised by TDI offers the best improvement in low temperature performance.It is worth noting that the PU synthesised by MDI provides a more balanced improvement in high and low temperature performances.This study provides guidance for the development of PU modified bitumen.
基金National Natural Science Foundation of China(62375274)Key Deployment Project of Chinese Academy of Sciences(KGFZD-145-24-12)Shanghai Industrial Collaborative Innovation Project(XTCX-KJ-2023-01)。
文摘Femtosecond pulsed lasers offer significant advantages for micro-/nano-modifications in integrated photonics.Microring resonators(MRRs),which are essential components in photonic integrated circuits(PICs),are widely employed in various fields,including optical communication,sensing,and filtering.In this study,we investigate the modification mechanisms associated with femtosecond laser interactions with MRRs fabricated on a lowpressure chemical vapor deposition(LPCVD)-silicon nitride(SiN)photonic platform,with emphasis on the post-fabrication trimming of second-order microring filters and MRR-based four-channel wavelength-division multiplexing(WDM).We examine 10 MRRs located at different positions on a wafer and discovered resonance wavelength shifts exceeding 1 nm due to fabrication-induced variations.Interactions between femtosecond lasers and LPCVD-SiN films resulted in silicon nanoclusters,which significantly redshifted the resonance wavelength of the MRRs.Additionally,the extinction ratio of MRRs improved by over 11.8 dB within the conventional band after laser modification.This technique is employed to enhance the performance of second-order MRRs and the four-channel WDM configuration,thus providing critical experimental evidence for leveraging femtosecond lasers to optimize LPCVD-SiN PICs.
基金The authors would also like to thank NIT,Durgapur RIG#2 project for financial support and the Director of National In-stitute of Technology Durgapur,India,for his continuous en-couragement.
文摘A near eutectic Al−12.6Si alloy was developed with 0.0wt%,2.0wt%,4.0wt%,and 6.0wt%Al−5Ti−1B master alloy.The micro-structural morphology,hardness,tensile strength,elongation,and fracture behaviour of the alloys were studied.The unmodified Al−12.6Si al-loy has an irregular needle and plate-like eutectic silicon(ESi)and coarse polygonal primary silicon(PSi)particles in the matrix-likeα-Al phase.The P_(Si),E_(Si),andα-Al morphology and volume fraction were changed due to the addition of the Al−5Ti−1B master alloy.The hardness,UTS,and elongation improved due to the microstructural modification.Nano-sized in-situ Al3Ti particles and ex-situ TiB_(2)particles caused the mi-crostructural modification.The fracture images of the developed alloys exhibit a ductile and brittle mode of fracture at the same time.The Al−5Ti−1B modified alloys have a more ductile mode of fracture and more dimples compared to the unmodified alloy.
基金The authors are grateful for Open Fund of Key Laboratory of Ministry of Education for metallurgical emission reduction and comprehensive utilization of resources(JKF19-08),General Project of Science and Technology Plan of Yunnan Science and Technology Department(2019FB077 and 202001AT070029)the Open Fund of Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education(Grant No.FMRUlab-20-4).
文摘Fe-loaded activated carbon(AC)has high surface acidity and more active sites,while manganese-loaded AC has high oxygen content.Coconut husk AC modified by Fe-Mn was studied with the aim of revealing the modification mechanism.First,HNO_(3)AC was prepared using the nitric acid immersion method.Second,Fe-Mn/AC was prepared using the Fe(N0_(3))_(3)and Mn(N0_(3))_(2)sequential immersion.The effects of HNO_(3),Fe(N0_(3))_(3),and Mn(N0_(3))_(2)on the pore texture and surface chemical characteristics of carbon materials were examined by scanning electron microscopy,Brunauer-Emmett-Teller(BET)analysis,X-ray diffraction and Fourier-transform infrared spectroscopy.The surface topography,pore structure,active material,and functional groups of AC,HNO_(3)/AC,and Fe-Mn/AC were systematically studied.The following results were obtained.The surface of HNO_(3)AC has more ditches and air voids;the micropores of HNO_(3)AC are deformed and flattened compared to those of AC.The surface of Fe-Mn/AC exhibits an accumulation phenomenon.MnFe_(2)O_(4)and FeMn_(2)O_(4)formed more pore structures.AC and HNO_(3)AC have numerous micropores.The higher loading quantity of Fe-Mn results in bigger specific surface.The active components of Fe-Mn/AC-1,Fe-Mn/AC-2,Fe-Mn/AC-3,and Fe-Mn/AC-4 are MnFe_(2)O_(4),MnO_(0.43)Fe_(2.57)O_(4),Mn_(3)O_(4),and ot-Fe_(2)O_(3)>respectively.The surface functional groups of AC and HNO_(3)AC are oxygen-containing functional groups.The effect of Fe-Mn modifying conditions on functional group species is rare;however,Fe/AC has more oxygen-containing functional groups.These research findings can aid in the desulfurization and denitrification of the Fe-Mn/AC catalyst.
基金supported by the National Natural Science Foundation of China (No. U 1507123)the Foundation from Qinghai Science and Technology Department (No. 2014-HZ-817)
文摘A calcium sulfate whisker （CSW） coated with glutaraldehyde crosslinked chitosan （GACS） was prepared to reinforce polyvinyl chloride （PVC） in this study. The results show that the optimum concentration of both chitosan （CS） and glutaraldehyde （GA） is 0.05 wt%. The tensile strength, impact strength, flexural modulus and vicat softening temperature of the PVC composite with 12 wt% of modified CSW are in- creased by 1 Z5%, 40.4%, 0.8% and 3.8% compared with those of the PVC composite with 12 wt~ of unmodified CSW, and by 2.9%, 42.4%, 2Z1% and 6.8% compared with those of pure PVC, respectively. The dynamic mechanical analysis results indicate that the modified CSW/PVC composite exhibits much higher storage modulus and glass transition temperature than those of unmodified CSW/PVC composite and pure PVC. In addition, the modified CSW/PVC composite also demonstrates good thermal properties with a high rapidest decomposition temperature （Trvd） and char residue. The scanning electron microscopy images of tensile-fractured surfaces show that the modified CSW has a strong interfacial adhesion with PVC matrix.
