Effect of wear conditions on tribological properties of electrolessly-deposited Ni-P-Gr-SiC hybrid composite coating

The friction and wear properties of the electrolessly-deposited Ni-P-Gr-SiC composites were investigated. The effects of graphite content, load and rotation speed on the friction coefficient and wear resistance of the composite coatings were mainly investigated. The worn surface and cross section of the coatings were characterized by scanning electron microscopy and energy-dispersive X-ray analysis. The results show that the composite coatings reveal good antifriction and wear resistance due to the synergic effect of graphite and SiC particles. The formation of graphite-rich mechanically mixed layer （GRMML） on the surface of Ni-P-Gr-SiC coating contributes to the good tribological behavior of the wear counterparts and SiC particles play a load bearing role in protecting GRMML from shearing easily.

Synergistic Effect of Adjuvant Green Orange Peel Oil on Different Herbicides

[Objective] The paper was to explore the synergistic effect of a novel adjuvant green orange peel oil on different herbicides in direct sowing paddy field. [Method] The synergistic test of green orange peel oil on 10% cyanoflurate SC and 10% metamifop EC was conducted in 2019.[Result] The control effect of green orange peel oil 150 mL/hm^(2)+ 10% cyanoflurate SC 1 275 mL/hm^(2) on Echinochloa crusgalli and Leptochloa chinensis were significantly superior to that of 10% cyanoflurate SC 1 500 mL/hm^(2). The control effects of green orange peel oil 150 m L/hm^(2)+10%cyanoflurate SC 1 200 m L/hm^(2) on E. crusgalli and L. chinensis was equivalent to that of 10% cyanoflurate SC 1 500 mL/hm^(2). The control effect of green orange peel oil 150 mL/hm^(2)+ 10% metamifop EC 1 275 mL/hm^(2) on E. crusgalli and L. chinensis was equivalent to that of 10% metamifop EC 1 500 m L/hm^(2). [Conclusion] The green orange peel oil had certain synergistic effect on cyanoflurate and metamifop.

Compositional engineering of HKUST-1/sulfidized NiMn-LDH on functionalized MWCNTs as remarkable bifunctional electrocatalysts for water splitting

Water-splitting reactions such as the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER)typically require expensive noble metal-based electrocatalysts.This has motivated researchers to develop novel,cost-effective electrocatalytic systems.In this study,a new multicomponent nanocomposite was assembled by combining functionalized multiwalled carbon nanotubes,a Cu-based metal–organic framework(MOF)(HKUST-1 or HK),and a sulfidized NiMn-layered double hydroxide(NiMn-S).The resulting nanocomposite,abbreviated as MW/HK/NiMn-S,features a unique architecture,high porosity,numerous electroactive Cu/Ni/Mn sites,fast charge transfer,excellent structural stability,and conductivity.At a current density of 10 mA cm-2,this dual-function electrocatalyst shows remarkable performance,with ultralow overpotential values of 163 mV(OER)or 73 mV(HER),as well as low Tafel slopes(57 and 75 mV dec-1,respectively).Additionally,its high turnover frequency values(4.43 s-1 for OER;3.96 s-1 for HER)are significantly superior to those of standard noble metal-based Pt/C and IrO2 systems.The synergistic effect of the nanocomposite's different components is responsible for its enhanced electrocatalytic performance.A density functional theory study revealed that the multi-interface and multicomponent heterostructure contribute to increased electrical conductivity and decreased energy barrier,resulting in superior electrocatalytic HER/OER activity.This study presents a novel vision for designing advanced electrocatalysts with superior performance in water splitting.Various composites have been utilized in water-splitting applications.This study investigates the use of the MW/HK/NiMn-S electrocatalyst for water splitting for the first time to indicate the synergistic effect between carbon-based materials along with layered double hydroxide compounds and porous compounds of MOF.The unique features of each component in this composite can be an interesting topic in the field of water splitting.

Gradient carbonyl-iron/carbon-fiber reinforced composite metamaterial for ultra-broadband electromagnetic wave absorption by multi-scale integrated design

The demand of high-end electromagnetic wave absorbing materials puts forward higher requirements on comprehensive performances of small thickness,lightweight,broadband,and strong absorption.Herein,a novel multi-layer stepped metamaterial absorber with gradient electromagnetic properties is proposed.The complex permittivity and permeability of each layer are tailored via the proportion of carbonyliron and carbon-fiber dispersing into the epoxy resin.The proposed metamaterial is further optimized via adjusting the electromagnetic parameters and geometric sizes of each layer.Comparing with the four-layer composite with gradient electromagnetic properties which could only realize reflection loss(RL)of less than−6 dB in 2.0-40 GHz,the optimized stepped metamaterial with the same thickness and electromagnetic properties realizes less than−10 dB in the relevant frequency range.Additionally,the RL of less than−15 dB is achieved in the frequency range of 11.2-21.4 GHz and 28.5-40 GHz.The multiple electromagnetic wave absorption mechanism is discussed based on the experimental and simulation results,which is believed to be attributed to the synergy effect induced by multi-scale structures of the metamaterial.Therefore,combining multi-layer structures and periodic stepped structures into a novel gradient absorbing metamaterial would give new insights into designing microwave absorption devices for broadband electromagnetic protections.

Tribocorrosion behaviors of Ti-6Al-4V and Monel K500 alloys sliding against 316 stainless steel in artificial seawater

The tribocorrosion behaviors of Ti-6Al-4V and Monel K500 alloys sliding against 316 stainless steel were investigated using a ring-on-block test rig in both artificial seawater and distilled water. It is found that friction coefficients are in general larger in distilled water compared with seawater. The wear losses of Ti-6Al-4V and Monel K500 alloys are larger in seawater compared with distilled water. The mechanical action can destroy the passive film and increase the corrosion rate. The synergism effect between corrosion and wear occurs. The synergism action between corrosion and wear is related to the corrosion rate and with the increase of corrosion rate, the synergism becomes more important. 316 stainless steel suffers severe wear sliding against Monel K500 alloy compared with sliding against Ti-6Al-4V alloy in both distilled water and seawater.

Selective tandem hydrogenation and rearrangement of furfural to cyclopentanone over CuNi bimetallic catalyst in water

Tandem catalysis for the hydrogenation rearrangement of furfural(FA)provides an attractive solution for manufacturing cyclopentanone(CPO)from renewable biomass resources.The Cu-Ni/Al-MCM-41 catalyst was synthesized and afforded excellent catalytic performance with 99.0%conversion and 97.7%selectivity to CPO in a near-neutral solution under 2.0 MPa H2 at 160℃ for 5 h,much higher than those on other molecular sieve supports including MCM-41,SBA-15,HY,and ZSM-5.A small amount of Al highly dispersed in MCM-41 plays an anchoring role and ensures the formation of highly dispersed CuNi bimetallic nanoparticles(NPs).The remarkably improved catalytic performance may be attributed to the bimetallic synergistic and charge transfer effects.In addition,the initial FA concentration and the aqueous system pH required precise control to minimize polymerization and achieve high selectivity of CPO.Fourier transform infrared spectroscopy and mass spectra results indicated that polymerization was sensitive to pH values.Under acidic conditions,FA and intermediate furfuryl alcohol polymerize,while the intermediate 4-hydroxy-2-cyclopentenone mainly polymerizes under alkaline conditions,blocking the cascade of multiple reactions.Therefore,near-neutral conditions are most suitable for minimizing the impact of polymerization.This study provides a useful solution for the current universal problems of polymerization side reactions and low carbon balance for biomass conversion.

An efficient Approach to Modify the Catalyst Activity for the Hydrogenation of Nitrobenzene

The addition of a suitable amount of PPh3 to PdCl2 or PdCl2(PhCN)(2) in situ can considerably increase the catalytic activity in the hydrogenation of nitrobenzene, while the catalytic activities of PdCl2 (reduced)+PPh3, PdCl2(PPh3)(2) and Pd(PPh3)(4) are very poor. The poisoning of catalyst by mercury indicates that the catalytically active species are composed of Pd(0) colloidal particles. Transmission electron micrographs show that the size of nanometric Pd(0) particles of PdCl2 with PPh3 added in situ is smaller than that of PhCl2(PPh3) or PdCl2 (reduced)+PPh3. A synergic effect of bimetallic catalysts such as PdCl2+nPPh(3)+NiCl2 (n= 0.5, 1) and PdCl2(PhCN)(2)+PPh3+FeCl3 gives rise to a further increase in the catalytic activity.

Synthesis of Dimethyl Ether from CO Hydrogenation: a Thermodynamic Analysis of the Influence of Water Gas Shift Reaction

Three reactions involved in dimethyl ether (DME) synthesis from COhydrogenation: methanol synthesis reaction (MSR), methanol dehydration reaction (MDR) and water gasshift reaction (WGSR) are studied by thermodynamic calculation. For demonstrating this process indetail, three models, MSR, MSR+MDR, MSR+MDR+WGSR, are used. Their basic characteristics can beobtained by varying widely the ratios of H_2 to CO in the feed (no CO_2). Through thermodynamicanalysis a chemical synergic effect obviously exists in the second and third models. By comparisonbetween two models it is found that WGSR plays a special role in dimethyl ether synthesis. It ispossible for the two models to shift one to the other by regulating CO_2 concentration in feed. ForModel 2, the selectivity for DME in oxygenates (DME+methanol) does not change with the ratio of H_2to CO.

Electrically enhanced photodegradation of an azodye(Acid Orange II) using a Pt/TiO_2 film electrode irradiating with an UV lamp

A photoelectrochemical process in the degradation of an azodye (Acid Orange II) on a Pt/TiO 2 film electrode was investigated. By using the glass device and the voltage stabilized source of direct current, decolorization ratios higher than 78% were observed during a period of 5h. Comparing this value with the sum of the decolorization ratios obtained by a sole application of electrochemical(lower than 3%) and photochemical(about 23%) procedures, a significant synergic effect between both processes was observed. The effects of adscititious voltage and pH value on the decolorization ratios were obvious while the effect of the amount of aeration was minor.

Abatement of SO_2–NOx binary gas mixtures using a ferruginous active absorbent:Part I. Synergistic effects and mechanism

A novel ferruginous active absorbent, prepared by fly ash, industrial lime and the additive Fe（VI）, was introduced for synchronous abatement of binary mixtures of SO2–NOx from simulated coal-fired flue gas. The synergistic action of various factors on the absorption of SO2 and NOx was investigated. The results show that a strong synergistic effect exists between Fe（VI） dose and reaction temperature for the desulfurization. It was observed that in the denitration process, the synergy of Fe（VI） dose and Ca/（S ＋ N） had the most significant impact on the removal of NO, followed by the synergy of Fe（VI） and reaction temperature, and then the synergy of reaction temperature and flue gas humidity. A scanning electron microscope（SEM） and an accessory X-ray energy spectrometer（EDS）were used to observe the surface characteristics of the raw and spent absorbent as well as fly ash. A reaction mechanism was proposed based on chemical analysis of sulfur and nitrogen species concentrations in the spent absorbent. The Gibbs free energy, equilibrium constants and partial pressures of the SO2–NOx binary system were determined by thermodynamics.

Enhanced heterogeneous activation of peroxymonosulfate by boosting internal electron transfer in a bimetallic Fe_(3)O_(4)-MnO_(2) nanocomposite

Transition metal-based bimetallic oxides can effectively activate peroxymonosulfate(PMS) for the degradation of organic contaminants, which may be attributed to the enhanced electron transfer efficiency between transition metals. Here, we investigated the high-efficiency catalytic activation reaction of PMS on a well-defined bimetallic Fe-Mn nanocomposite(BFMN) catalyst. The surface topography and chemical information of BFMN were simultaneously mapped with nanoscale resolution. Rhodamine B(Rh B, as a model pollutant) was used to evaluate the oxidation activity of PMS activation system. The maximum absorption peak of Rh B obviously blue shifted from 554 nm to 501 nm, and decreased sharply to disappear completely within 60 min. The removal performance is better than most of the reported single transition metal oxide. X-ray photoelectron spectroscopy(XPS) imaging of the BFMN electronic structure after catalytic activation confirmed that the accelerated internal electron transfer is mainly caused by the synergy effect of Mn and Fe sites at the catalysis boundary. The outstanding ability of BFMN for PMS chemical adsorption and activation may attribute to the enhanced covalency and reactivity of Mn-O. These results of this study can advance understandings on the origins of bimetallic oxides activity for PMS activation and developing the efficient metal oxide catalysts in real practice.

Tailoring morphology and bulk density of magnesium ethoxide particles by adding n-hexane and silicone oil

In this work,we used the in ert substances silic one oil a nd n-hexane to modulate the solve nt environ ment,and in so doing tailor the preparation of magnesium ethoxide(Mg(0Et)2)particles.We found the following:(1)non polar n-hexane mainly modulates the polarity of the solvent to control the precipitation rate and size of the Mg(OEt)2 seeds,thereby triggering accelerated nucleation to form small primary particles;and(2)silicone oil(relatively high polarity and viscosity)facilitates the growth and agglomeration stage,to improve inter-particle dispersion and obtain relatively uniform Mg(OEt)2 particles.We summarized these findings in a comm on mechanism for preparing Mg(OEt)2 particles with uniform morphology,small size,and high bulk density as per the synergistic effect of n-hexane and silicone oil.The ratios of silicone oil end n-hexane are flexible,and afford various regular and well-dispersed Mg(OEt)2 particles that are 5-30μm in size and 0.2-0.7 g/cm^3 in bulk density.The nanoparticles thus have the potential to serve in diverse applications such as catalysis.

Photo-functionalized TiO_(2) nanotubes decorated with multifunctional Ag nanoparticles for enhanced vascular biocompatibility

Titanium dioxide(TiO2)has a long history of application in blood contact materials,but it often suffers from insufficient anticoagulant properties.Recently,we have revealed the photocatalytic effect of TiO2 also induces anticoagulant properties.However,for long-term vascular implant devices such as vascular stents,besides anticoagulation,also anti-inflammatory,anti-hyperplastic properties,and the ability to support endothelial repair,are desired.To meet these requirements,here,we immobilized silver nanoparticles(AgNPs)on the surface of TiO2 nanotubes(TiO2-NTs)to obtain a composite material with enhanced photo-induced anticoagulant property and improvement of the other requested properties.The photo-functionalized TiO2-NTs showed protein-fouling resistance,causing the anticoagulant property and the ability to suppress cell adhesion.The immobilized AgNPs increased the photocatalytic activity of TiO2-NTs to enhances its photo-induced anticoagulant property.The AgNP density was optimized to endow the TiO2-NTs with anti-inflammatory property,a strong inhibitory effect on smooth muscle cells(SMCs),and low toxicity to endothelial cells(ECs).The in vivo test indicated that the photofunctionalized composite material achieved outstanding biocompatibility in vasculature via the synergy of photo-functionalized TiO2-NTs and the multifunctional AgNPs,and therefore has enormous potential in the field of cardiovascular implant devices.Our research could be a useful reference for further designing of multifunctional TiO2 materials with high vascular biocompatibility.

Preliminary Evaluation of a Candidate Multi-Epitope-Vaccine Against the Classical Swine Fever Virus

A multi-epitope-vaccine MEVABc consisting of two linear neutralizing determinants （BCI： aa693-716; A6： aa844-865） located on antigenic unit B/C and unit A of glycoprotein E2 was prepared to evaluate whether a combination strategy is effective in the design of peptide vaccines. After immunization, pig sera collected every one to two weeks were evaluated by enzyme linked immunosorbent assay. C-straininduced anti-sera and hyper-immune sera cannot recognize overlapping peptides that cover the E2 N-terminus, while MEVAgC is able to elicit high levels of peptide-specific antibody response. When compared with previously studied peptide vaccines PV-BC1 and PV-A6, the same dose of either component in the MEMABc increases the BC1- or A6-specific antibodies （to 1/3-1/2 of the levels of the separate vaccines）. However, the synergy between the antibodies may make MEVAgc much more potent. Moreover, anti-C-strain immunity pre-existing in pigs does not disturb the sequent MEVABc vaccination. Thus, MEVABc can be administrated to pigs which already possess anti-classical swine fever virus immunity. MEVAgC is a promising candidate marker vaccine.