Themanganese-cobalt mixed oxide nanorodswere fabricated using a hydrothermalmethod with different metal precursors(KMnO_(4)and MnSO_(4)·H_(2)O for MnOx and Co(NO3)2>6H_(2)O and CoCl_(2)>6H_(2)O for Co_(3)O_...
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Themanganese-cobalt mixed oxide nanorodswere fabricated using a hydrothermalmethod with different metal precursors(KMnO_(4)and MnSO_(4)·H_(2)O for MnOx and Co(NO3)2>6H_(2)O and CoCl_(2)>6H_(2)O for Co_(3)O_(4)).Bamboo-like MnO_(2)>Co_(3)O_(4)(B-MnO_(2)>Co_(3)O_(4)(S))was derived from repeated hydrothermal treatments with Co_(3)O_(4)@MnO_(2)and MnSO_(4)>H_(2)O,whereas Co_(3)O_(4)@MnO_(2)nanorods were derived from hydrothermal treatment with Co_(3)O_(4)nanorods and KMnO_(4).The study shows that manganese oxide was tetragonal,while the cobalt oxide was found to be cubic in the crystalline *** surface ions were present in multiple oxidation states(e.g.,Mn^(4+)and Mn^(3+))and surface oxygen *** content of adsorbed oxygen species and reducibility at low temperature declined in the sequence of BMnO_(2)>Co_(3)O_(4)(S)>Co_(3)O_(4)@MnO_(2)>MnO_(2)>Co_(3)O_(4),matching the changing trend in *** all the samples,B-MnO_(2)>Co_(3)O_(4)(S)showed the preeminent catalytic performance for the oxidation of toluene(T10%=187℃,T50%=276℃,and T90%=339℃).In addition,the B-MnO_(2)>Co_(3)O_(4)(S)sample also exhibited good H_(2)O^(-),CO_(2)^(-),and SO_(2)^(-)resistant *** good catalytic performance of B-MnO_(2)>Co_(3)O_(4)(S)is due to the high concentration of adsorbed oxygen species and good reducibility at low *** oxidation over B-MnO_(2)>Co_(3)O_(4)(S)proceeds through the adsorption of O_(2)and toluene to form O∗,OH∗,and H_(2)C(C6H5)∗species,which then react to produce benzyl alcohol,benzoic acid,and benzaldehyde,ultimately converting to CO_(2)and H_(2)*** findings suggest that B-MnO_(2)>Co_(3)O_(4)(S)has promising potential for use as an effective catalyst in practical applications.
MnCeO_(x)/P84 catalytic filters with spherical,flower-like,cubic and rod-like catalytic interfaces were synthesized respectively,and their catalytic activities in the NH_(3)-SCR reaction were *** MnCeO_(x)/P84 catalyt...
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MnCeO_(x)/P84 catalytic filters with spherical,flower-like,cubic and rod-like catalytic interfaces were synthesized respectively,and their catalytic activities in the NH_(3)-SCR reaction were *** MnCeO_(x)/P84 catalytic filter with spherical catalytic interfaces(recorded as S-MnCeO_(x)/P84)exhibits the best catalytic denitration *** NO_(x)removal efficiency of S-MnCeO_(x)/P84 reaches the highest value of 98.6%at 160℃when the catalyst loading is 100 g/m^(2).At the same time,S-MnCeO_(x)/P84 exhibits good SO_(2)resistance and stability,achieving a NO_(x)removal rate of 83%at 190℃with 30 ppm SO_(2).The characterization results illustrate that the MnCeO_x active component in S-MnCeO_(x)/P84 is present in weak crystalline states,tightly wrapped around the surface of the filter fiber,and uniformly dispersed,and the mesopore is the main pore structure of the S-MnCeO_(x)/P84,which can provide a channel for the catalytic reaction to *** the same time,transmission electron microscopy(TEM)characterization shows that y-MnO_(2)is the main form of MnO_(2)in the S-MnCeO_(x)/*** analysis of H_(2)temperature programmed reduction(H_(2)-TPR).NH_(3)temperature programmed desorption(NH_(3)-TPD)and in-situ diffuse reflectance infrared spectra(DRIFTS)show that S-MnCeO_(x)/P84 has good redox ability at 100-200℃and has abundant Lewis acid sites and Bronsteds acid sites,which provides an important guarantee for its superior low-temperature NH_(3)-SCR denitration performance.
The effects of projectile/target impedance matching and projectile shape on energy,momentum transfer and projectile melting during collisions are investigated by numerical *** comparing the computation results with th...
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The effects of projectile/target impedance matching and projectile shape on energy,momentum transfer and projectile melting during collisions are investigated by numerical *** comparing the computation results with the experimental results,the correctness of the calculation and the statistical method of momentum transfer coefficient is *** shapes of aluminum,copper and heavy tungsten alloy projectiles striking aluminum,basalt,and pumice target for impacts up to 10 km/s are *** influence mechanism of the shape of the projectile and projectile/target density on the momentum transfer was *** an increase in projectile density and length-diameter ratio,the energy transfer time between the projectile and targets is *** projectile decelerates slowly,resulting in a larger cratering *** energy consumed by the projectile in the excavation stage increased,resulting in lower mass-velocity of ejecta and momentum transfer *** numerical simulation results demonstrated that for different projectile/target combinations,the higher the wave impedance of the projectile,the higher the initial phase transition velocity and the smaller the mass of phase *** results can provide theoretical guidance for kinetic impactor design and material selection.
To enrich material types applied to additive manufacturing and enlarge application scope of additive manufacturing in conformal cooling tools,M2 high-speed steel specimens were fabricated by selective laser melting(SL...
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To enrich material types applied to additive manufacturing and enlarge application scope of additive manufacturing in conformal cooling tools,M2 high-speed steel specimens were fabricated by selective laser melting(SLM).Effects of SLM parameters on the microstructure and mechanical properties of M2 high-speed steel were *** results showed that substrate temperature and energy density had significant influence on the densification process of materials and defects *** to evaluate the effect of substrate temperature and energy density on hardness were *** optimized process parameters,laser power,scan speed,scan distance,and substrate temperature,for fabricated M2 are 220 W,960 mm/s,0.06 mm,and 200℃,*** on this,the hardness and tensile strength reached 60 HRC and 1000 MPa,*** crack formation and suppression mechanism and the relationship between temperature gradient and thermal stress were *** inhibition effect of substrate temperature on the cracks generated by residual stresses was also *** showed great application potential in the field of special conformal cooling cutting tool preparation.
Electrochemical oxidation is an effective method to degrade persistent organic ***,due to the limited catalytic activity of traditional thin film electrodes,the anodic oxidation process is slow and usually requires hi...
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Electrochemical oxidation is an effective method to degrade persistent organic ***,due to the limited catalytic activity of traditional thin film electrodes,the anodic oxidation process is slow and usually requires high energy ***,Ti/SnO_(2)-Sb electrode with regulated surface structure was reported to enhance the performance for electrochemical oxidation of persistent organic *** electrode deposited with SnO_(2)-Sb nanoneedles(Ti/N-SnO_(2)-Sb)showed higher oxidation *** kinetic constant for perfluorooctanoic acid(PFOA)oxidation was 2.0 h^(-1)and the total organic carbon removal rate was 81.7%(4 h)at a relatively low current density of 6 mA/cm^*** with Ti/SnO_(2)-Sb thin film and nanoparticles,Ti/N-SnO_(2)-Sb significantly improved the electrochemical active area and·OH yield,and simultaneously reduced the electron transfer resistance,which enabled it to oxidize PFOA more rapidly even at a lower *** work provides a new strategy for promoting the electrochemical oxidation performance.
Oxygen evolution reaction(OER)is one of the most important issues for hydrogen production from water *** the OER process,electrochemical reconstruction is widely observed for the majority of electrocatalysts,which is ...
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Oxygen evolution reaction(OER)is one of the most important issues for hydrogen production from water *** the OER process,electrochemical reconstruction is widely observed for the majority of electrocatalysts,which is strongly related to the formation and evolution of real active ***,bimetal metal-organic framework(MOF)with an equal ratio of Co and Fe sites is screened to exhibit the superior OER *** obvious reconstruction is observed to transform single MOF phase into the heterostructure composed of active CoOOH and ***,the generation of Co^(3+)species is more reliant on the blessing of electricity and electrolyte than that of Fe3+*** a result,the optimal electrocatalyst shows the overpotential of 267 mV at 10 mA/cm^(2)and ultra-low Tafel slope of 24.7 mV/dec with a stable OER performance.
High piezoelectric composite films composed of poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)and ferromagnetic cobalt ferrite(CoFe_(2)O_(4))(0.00 wt%to 0.2 wt%)are prepared by a solution casting method acc...
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High piezoelectric composite films composed of poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)and ferromagnetic cobalt ferrite(CoFe_(2)O_(4))(0.00 wt%to 0.2 wt%)are prepared by a solution casting method accompanied by uniaxial stretching and high electric field *** decisive effect of the poling electric field on the power generating capability was confirmed by the *** pure PVDF-HFP films,when the maximum electric field Emax is 120 MV/m,the calibrated open circuit voltage reaches 2.93 V,which is much higher than those poled at lower electric fields(70 MV/m:1.41 V;90 MV/m:2.11 V).Furthermore,the addition of CoFe_(2)O_(4)also influences the piezoelectricity *** the samples containing 0.15 wt%CoFe_(2)O_(4),the calibrated open circuit voltage increases to the maximum value of 3.57 ***,the relative fraction of theβ-phase and the crystallinity degree are 99%and 48%,*** effects of CoFe_(2)O_(4)nanoparticles on initial crystallization,uniaxial stretching and high electric field poling are investigated by XRD,FTIR and DSC.
One-stage partial nitrification coupled with anammox(PN/A)technology effectively reduces the energy consumption of a biological nitrogen removal *** nitrite-oxidizing bacteria(NOB)is essential for this technology to m...
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One-stage partial nitrification coupled with anammox(PN/A)technology effectively reduces the energy consumption of a biological nitrogen removal *** nitrite-oxidizing bacteria(NOB)is essential for this technology to maintain efficient nitrogen removal *** ammonium concentration(IAC)affects the degree of inhibited *** this study,the effect of the IAC on a PN/A biofilm was investigated in a moving bed biofilm *** results showed that nitrogen removal efficiency decreased from 82.49%±1.90%to 64.57%±3.96%after the IAC was reduced from 60 to 20 mg N/L,while the nitrate production ratio increased from 13.87%±0.90%to 26.50%±3.76%.NOB activity increased to1,133.86 mg N/m^(2)/day after the IAC decreased,approximately 4-fold,indicating that the IAC plays an important inhibitory role in *** rate-limiting step in the mature biofilm of the PN/A system is the nitritation process and is not shifted by the *** analysis of the microbial community structure in the biofilm indicates that the IAC was the dominant factor in changes in community *** and *** were the main anammox bacteria,and Nitrosomonas and Nitrospira were the main AOB and NOB,*** did not affect the difference in growth between *** and ***,modulating the IAC promoted the PN/A process with efficient nitrogen removal performance at medium to low ammonium concentrations.
Dense pre-hydrated geosynthetic clay liners(DPH GCLs)were manufactured as innovative materials accompanied by the advantage of lower hydraulic conductivity(k).The k of DPH GCLs permeated with de-ionized water(DIW)was ...
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Dense pre-hydrated geosynthetic clay liners(DPH GCLs)were manufactured as innovative materials accompanied by the advantage of lower hydraulic conductivity(k).The k of DPH GCLs permeated with de-ionized water(DIW)was 9.8×10^(−12) m/*** effect of Cu^(2+)synthetic solution on DPH GCLs was ***,the effect mechanism was studied on the basis of test technologies.A significant adverse impact on hydraulic performance of DPH GCLs is found when the concentration of Cu^(2+)is greater than 1 g/***,XRD,XRF,FTIR,and XPS analyses show that the effect of Cu^(2+)on DPH GCLs includes two ***,Cu^(2+)interacts with hydrophobic organic matter(HOM),and the adhesion of bentonite is destroyed,and some holes *** Cu^(2+)contacts with bentonite directly,and Cu^(2+)interacts with bentonite through ion *** phenomenon occurs on the surface of the bentonite,and swelling ability of bentonite is reduced,which causes permeable DPH GCLs.
Soft magnetic composite(SMC)material is an ideal soft magnetic material employed for developing 3D magnetic flux electromagnetic equipment,due to its advantages of 3D magnetic isotropy characteristic,low eddy current ...
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Soft magnetic composite(SMC)material is an ideal soft magnetic material employed for developing 3D magnetic flux electromagnetic equipment,due to its advantages of 3D magnetic isotropy characteristic,low eddy current loss,and simple manufacturing *** permanent magnet claw pole machine(PMCPM)with SMC cores is a good case that the SMC to be adopted for developing 3D flux electrical *** this paper,a novel axial-radial flux permanent magnet claw pole machine(ARPMCPM)with SMC cores and ferrite magnets is *** with the traditional PMCPM,the proposed ARPMCPM is designed with only one spoke PM rotor and its whole structure is quite *** the performance prediction,the 3D finite element method(FEM)is ***,for the performance evaluation,a previously developed axial flux claw pole permanent magnet machine(AFCPM)is employed as the benchmark machine and all these machines are optimized by using the combined multilevel robust Taguchi *** can be seen that the proposed ARPMCPM is with higher torque/weight density and operation efficiency.
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