Composite polymer electrolytes(CPEs)offer a promising solution for all-solid-state lithium-metal batteries(ASSLMBs).However,conventional nanofillers with Lewis-acid-base surfaces make limited contribution to improving...Composite polymer electrolytes(CPEs)offer a promising solution for all-solid-state lithium-metal batteries(ASSLMBs).However,conventional nanofillers with Lewis-acid-base surfaces make limited contribution to improving the overall performance of CPEs due to their difficulty in achieving robust electrochemical and mechanical interfaces simultaneously.Here,by regulating the surface charge characteristics of halloysite nanotube(HNT),we propose a concept of lithium-ion dynamic interface(Li^(+)-DI)engineering in nano-charged CPE(NCCPE).Results show that the surface charge characteristics of HNTs fundamentally change the Li^(+)-DI,and thereof the mechanical and ion-conduction behaviors of the NCCPEs.Particularly,the HNTs with positively charged surface(HNTs+)lead to a higher Li^(+)transference number(0.86)than that of HNTs-(0.73),but a lower toughness(102.13 MJ m^(-3)for HNTs+and 159.69 MJ m^(-3)for HNTs-).Meanwhile,a strong interface compatibilization effect by Li^(+)is observed for especially the HNTs+-involved Li^(+)-DI,which improves the toughness by 2000%compared with the control.Moreover,HNTs+are more effective to weaken the Li^(+)-solvation strength and facilitate the formation of Li F-rich solid-electrolyte interphase of Li metal compared to HNTs-.The resultant Li|NCCPE|LiFePO4cell delivers a capacity of 144.9 m Ah g^(-1)after 400 cycles at 0.5 C and a capacity retention of 78.6%.This study provides deep insights into understanding the roles of surface charges of nanofillers in regulating the mechanical and electrochemical interfaces in ASSLMBs.展开更多
Face-centered cubic (f.c.c.) high entropy alloys (HEAs) are attracting more and more attention owing to their excellent strength and ductility synergy, irradiation resistance, etc. However, the yield strength of f.c.c...Face-centered cubic (f.c.c.) high entropy alloys (HEAs) are attracting more and more attention owing to their excellent strength and ductility synergy, irradiation resistance, etc. However, the yield strength of f.c.c. HEAs is generally low, significantly limiting their practical applications. Recently, the alloying of W has been evidenced to be able to remarkably improve the mechanical properties of f.c.c. HEAs and is becoming a hot topic in the community of HEAs. To date, when W is introduced, multiple strengthening mechanisms, including solid-solution strengthening, precipitation strengthening (μphase,σphase, and b.c.c. phase), and grain-refinement strengthening, have been discovered to be activated or enhanced. Apart from mechanical properties, the addition of W improves corrosion resistance as W helps to form a dense WO_(3) film on the alloy surface. Until now, despite the extensive studies in the literature, there is no available review paper focusing on the W doping of the f.c.c. HEAs. In that context, the effects of W doping on f.c.c. HEAs were reviewed in this work from three aspects, i.e., microstructure,mechanical property, and corrosion resistance. We expect this work can advance the application of the W alloying strategy in the f.c.c. HEAs.展开更多
In cold regions,slope rocks are inevitably impacted by freeze-thaw,dry-wet cycles and their alternating actions,leading to strength weakening and pore degradation.In this study,the mechanical and microstructural prope...In cold regions,slope rocks are inevitably impacted by freeze-thaw,dry-wet cycles and their alternating actions,leading to strength weakening and pore degradation.In this study,the mechanical and microstructural properties of schist subjected to four conditions were investigated:freeze-thaw cycles in air(FTA),freeze-thaw cycles in water(FTW),dry-wet cycles(DW),and dry-wet-freeze-thaw cycles(DWFT).Uniaxial compressive strength(UCS),water absorption,ultrasonication,low-field nuclear magnetic resonance,and scanning electron microscopy analyses were conducted.The integrity attenuation characteristics of the longitudinal wave velocity,UCS,and elastic modulus were analyzed.The results showed that liquid water emerged as a critical factor in reducing the brittleness of schist.The attenuation function model accurately described the peak stress and static elastic modulus of schist in various media(R2>0.97).Different media affected the schist deterioration and half-life,with the FTW-immersed samples having a half-life of 28 cycles.Furthermore,the longitudinal wave velocity decreased as the number of cycles increased,with the FTW showing the most significant reduction and having the shortest half-life of 208 cycles.Moreover,the damage variables of compressive strength and elastic modulus increased with the number of cycles.After 40 cycles,the schist exposed to FTW exhibited the highest damage variables and saturated water content.展开更多
To achieve efficient catalytic hydrogenation of CO_(2)to formate,we employed a transmetallation strategy to develop three novel iridium(Ⅰ)complexes,which feature N‑heterocyclic carbene‑nitrogen‑phosphine ligands(CNP)...To achieve efficient catalytic hydrogenation of CO_(2)to formate,we employed a transmetallation strategy to develop three novel iridium(Ⅰ)complexes,which feature N‑heterocyclic carbene‑nitrogen‑phosphine ligands(CNP)and a 1,5‑cyclooctadiene(cod)molecule:[Ir(cod)(κ^(3)‑CN^(im)P)]Cl(1⁃Cl),[Ir(cod)(κ^(3)‑CN^(im)P)]PF6(1⁃PF_(6)),and[Ir(cod)(κ^(3)‑CNHP)]Cl(2).The^(1)H NMR spectra,^(31)P NMR spectra,and high‑resolution mass spectra verify the successful synthesis of these three Ir(Ⅰ)‑CNP complexes.Furthermore,single‑crystal X‑ray diffraction analysis confirms the coordination geometry of 1⁃PF_(6).The strong Ir—C(NHC)bond suggests that the carbene carbon plays an enhanced anchoring role to iridium due to its strongσ‑donating ability,which helps stabilize the active metal species during CO_(2)hydrogenation.As a result,the Ir(Ⅰ)‑CNP complex exhibits remarkable activity and long catalytic lifetime for the hydrogenation of CO_(2)to formate,reaching a turnover number(TON)of 1.16×10^(6)after 150 h at a high temperature of 170℃,which was a relatively high value among all the Ir complexes.CCDC:2384071,1⁃PF_(6).展开更多
Cadmium(Cd)or excess copper(Cu)has a great impact in terms of toxicity on living organisms as it severely affects crop growth,yield and food security;thus,warranting appropriate measures for the remediation of Cd or C...Cadmium(Cd)or excess copper(Cu)has a great impact in terms of toxicity on living organisms as it severely affects crop growth,yield and food security;thus,warranting appropriate measures for the remediation of Cd or Cu polluted soils.Phytoextraction of heavy metal(HM)using tolerant plants along with organic chelators has gained global attention,and this study provided further insights into this issue.Pot experiments were performed to evaluate the effects of different types of chelators[ethylenediamine tetraacetic acid(EDTA),ethylenediamine disuccinic acid(EDDS)and citric acid(CA)]to improve the phytoextraction capacity of Ricinus communis L.for the metals Cd and Cu.Contaminated soil from a copper smelter was used in this study.A rhizon soil sampler was used to determine the metal concentrations in soil pore water.The results indicated that R.communis was an adequate candidate for chelator induced phytoextraction under the experimental conditions and that EDDS would be a good candidate chelator for the phytoextraction of Cu in soils.EDTA addition obviously improved the uptake of Cd and Cu in R.communis;however,it posed the greatest risk because the concentration of HMs in soil pore water was very high even after 40 days.Compared with EDTA and EDDS,CA had few effects on Cd or Cu uptake in R.communis.Linear relationships between the metal uptake in R.communis shoots and the maximum HM concentrations in soil pore water under HM,2.5,5,and 10 mmol·kg^(-1) treatments were typically observed.From the results of this study,it could be concluded that EDDS treatments played a promising role in increasing the uptake of Cd or Cu and reducing its phytotoxicity.EDDS application could be an effective approach for the phytoextraction of Cd or Cu from polluted soils by growing Ricinus communis L.展开更多
The direct oxidation of methane to methanol(DOMM) has been recognized as a significant technology for efficiently utilizing low-concentration coalbed methane(LCMM) and supplying liquid fuel.Herein,the noble metals(Pt,...The direct oxidation of methane to methanol(DOMM) has been recognized as a significant technology for efficiently utilizing low-concentration coalbed methane(LCMM) and supplying liquid fuel.Herein,the noble metals(Pt,Pd and Ru) modified Cu/alkalized sepiolite(CuX/SEPA) catalysts were prepared and used for the DOMM in a gas-phase system at low temperatures.The CuRu/SEPA exhibited the highest methanol production of 53 μmol·g^(-1)·h^(-1) and methanol selectivity of 90% under the optimal reaction conditions.Various characterizations demonstrated that the addition of Ru promoted the formation of Cu^(2+)and the contraction of Cu—Si/Al bonds to reduce the distance between framework Al atoms of SEPA to further generate more Al pairs,which facilitated the formation of reactive dicopper species([Cu_(2)O]^(2+)or [Cu_(2)O_(2)]^(2+)).Investigation of the reaction mechanism revealed that [Cu_(2)O]^(2+) or [Cu_(2)O_(2)]^(2+) species could adsorb and activate methane to form CH_(3)O^(*) species and ultimately generated methanol with the assistance of water.展开更多
SnSe_(2) single crystals,as novel n-type plastic thermoelectric materials,present advantages such as envi-ronmental sustainability and cost-effectiveness.Single crystals of SnSe_(2)+x%PbBr_(2)(x=0,0.5,1,2,and 3)with l...SnSe_(2) single crystals,as novel n-type plastic thermoelectric materials,present advantages such as envi-ronmental sustainability and cost-effectiveness.Single crystals of SnSe_(2)+x%PbBr_(2)(x=0,0.5,1,2,and 3)with large size and high quality were successfully synthesized via the Bridgman method.The significant enhancement in power factor and effective suppression of lattice thermal conductivity can be achieved through PbBr_(2) doping,verifying a synergistic optimization of electrical and thermal transport properties.Specifically,Br atoms are effectively incorporated into the Se sites to manipulate the carrier concentra-tion and optimize the power factor,while simultaneously inducing a strong phonon softening effect by introducing Pb atoms at the Sn sites,which leads to a reduced phonon group velocity and a suppres-sion of lattice thermal conductivity.Consequently,SnSe_(2)+2%PbBr_(2) single-crystal sample achieves a peak figure of merit zT of~0.76 and an average zT of~0.51,giving rise to corresponding improvements of~533% and~538%,respectively,compared to the pristine SnSe_(2) sample,thereby outperforming most of the previously reported SnSe_(2)-based materials.This work provides a viable approach for promoting the thermoelectric performance of SnSe^(2)-based single crystals across a broad temperature range and supports the advancement of plastic thermoelectric materials.展开更多
Correction to:Rare Met.https://doi.org/10.1007/s12598-021-01815-z In the original publication,Fig.5 was published with few mistakes.The correct version of Fig.5 is given in this correction.
Proton exchange membrane fuel cells(PEMFCs)have gained increasing interests as promising power sources due to their ability to convert hydrogen and oxygen directly into electricity with high efficiency and zero greenh...Proton exchange membrane fuel cells(PEMFCs)have gained increasing interests as promising power sources due to their ability to convert hydrogen and oxygen directly into electricity with high efficiency and zero greenhouse gas emissions.Bipolar plates(BPs)are considered as a critical component of PEMFCs,serving to collect current,separate gases,distribute the flow field,and conduct heat.This paper reviews the technical status and advancements in BP materials,with special focus on strategies for enhancing interfacial contact resistance(ICR)and corrosion resistance through conductive polymer(CP)coatings.First,commonly used BP materials in PEMFCs are summarized.Then,the advantages and limitations of various coatings for metallic BPs are discussed.Finally,recent progress in CP coatings for metallic BPs,aimed at achieving high corrosion resistance and low ICR,is comprehensively reviewed.展开更多
Expanded polystyrene (EPS) is a common type of microplastics (MPs) often found in coastal areas especially aquaculture areas.It is considered as an important site for microbial colonization and biofilm formation,as we...Expanded polystyrene (EPS) is a common type of microplastics (MPs) often found in coastal areas especially aquaculture areas.It is considered as an important site for microbial colonization and biofilm formation,as well as a carrier of pollutants like heavy metals.However,the dynamic changes of bacterial communities attached to EPS and their interaction with heavy metals are still poorly unknown.In this study,a one-year field exposure experiment was conducted at an aquaculture farm near Donghai Island,in Leizhou Bay,Zhanjiang,Guangdong,in South China Sea.The bacterial communities attached to EPS MPs were examined by 16S r DNA high-throughput sequencing,and the relationships between bacterial biofilms and heavy metals were explored.The results show that there were notable seasonal variations in the bacterial diversity of EPS MPs.Species biodiversity was the highest in summer and the lowest in winter.The greatest number of bacterial species and lowest level of uniformity were observed in the spring.The bacterial community structure changed with exposure time,and the most significant difference in the 12-month group (P<0.05) was found.The dominant bacterial species attached to EPS MPs were mainly Proteobackteria and Firmicutes at the phylum level,and Pseudomonas and Exiguobacterium were dominant at the genus level.Furthermore,EPS MPs acted as transport carriers for potential pathogenic bacteria.High correlations were found between bacterial species and the total concentration of heavy metals on EPS MPs,as well as their speciation fractions.Different chemical speciation of heavy metals migrated and altered over seasons within biofilms,which would further exacerbate the ecological risks.展开更多
Alkaline slag is vital in rare earth steel refining,making it crucial to study the wetting and penetration mechanisms between refractory materials and slag.The effect of Eu_(2)O_(3) doping on the sintering properties ...Alkaline slag is vital in rare earth steel refining,making it crucial to study the wetting and penetration mechanisms between refractory materials and slag.The effect of Eu_(2)O_(3) doping on the sintering properties of MgO-MgAl_(2)O_(4) refractory materials was investigated while simulating the wetting behavior between the refractory and the CaO-Al_(2)O_(3)-SiO_(2)-MgO quaternary alkaline slag during rare earth steel smelting to improve the material’s resistance to alkaline slag corrosion.The doping of Eu_(2)O_(3) can alter the crystal structure parameters of MgAl_(2)O_(4) and MgO,causing lattice distortion.This lattice activation promotes interionic mass and diffusion,helping reduce porosity and promote densification of the material,further improving sintering properties.At the equilibrium wetting temperature(1723 K),Eu_(2)O_(3) doping increases the interfacial free energy between the slag and refractory material,reducing the spreading coefficient of the molten slag.The contact angle increases from 32.1°to 42.2°,and the residual slag volume increases from 17.9%to 23.5%.The results of thermodynamic analysis show that MgAl_(2)O_(4) and EuAlO3 formed at the interface block the penetration of molten slag at high temperatures,improving the resistance of MgO-MgAl_(2)O_(4) refractories to alkaline slag corrosion.Based on the capillary theory model,it was calculated that the capillary tension of the slag gradually increases with the addition of Eu_(2)O_(3),while the theoretical penetration depth of the slag gradually decreases.The experimental results showed that the slag erosion depth of the sample decreased from 102.54 to 68.28μm.展开更多
To improve the practical application of carbon steel,developing a superhydrophobic coating with outstanding mechanical properties is essential for effective corrosion resistance protection.Here,we obtained a robust su...To improve the practical application of carbon steel,developing a superhydrophobic coating with outstanding mechanical properties is essential for effective corrosion resistance protection.Here,we obtained a robust superhydrophobic anti-corrosion coating with a cauliflower structure by co-depositing the lauric acid with Ni ions and Mn ions onto a carbon steel through electrodeposition method.As demonstrated by the results,superhydrophobic Ni/Mn alloy(SNMAmit)displays a multi-hierarchical micro/nano cauliflower structure under the synergy of optimal parameters,exhibiting superb superhydrophobicity with contact angle of 161.9°and sliding angle of 6.2°.Surprisingly,the Tafel polarization curves in 3.5%NaCl showed that the corrosion potential of SNMAmit coating was 476 mV,and the corrosion current density was reduced from 1.39×10^(−5)to 5.89×10^(−7)A/cm^(2).The reduced corrosion current density of superhydrophobic Ni/Mn alloy(SNMA)indicates that SNMA coating can significantly enhance the anti-corrosion properties of carbon steel.In addition,after being subjected to various damages such as blade scraping,tape cyclic peeling,acid and alkalis,sandpaper cyclic abrasion,high temperatures,ultrasound,and graphite contaminant,SNMA showed good mechanical stability,interference resistance,heat resistance,and self-cleaning properties,which made it suitable for hostile conditions.展开更多
The metal triazole(MTA)-based MOFs were found to preferentially adsorb O-rich species,which had enhanced electrocatalytic oxygen reduction reactions(ORR)and stabilized the O-containing species during the discharge and...The metal triazole(MTA)-based MOFs were found to preferentially adsorb O-rich species,which had enhanced electrocatalytic oxygen reduction reactions(ORR)and stabilized the O-containing species during the discharge and charge processes in Li-O_(2)battery.However,the MOFs exhibited low electron conductivity and poor electron transfer interface in the electrocatalysis,limiting the electrocatalytic activity.To address this issue,a nanocomposite with the Co-MTA-coated carbon nano tubes(Co-MTA-C)was constructed,which formed the three-dimensional conductivity network connected with the intersecting carbon nano tube(CNT).In this composite,the electron-rich Co-MTA interacted with the highly conductive CNT,resulting in a charge redistribution.Optimized the electronic structure of the Co center through compositional modifications presented a high valence compared to the pure MOFs.In situ X-ray absorption spectroscopy revealed a direct reaction of Co sites with intermediates such as LiO_(x),leading to the formation of nanosheet array discharge products.The battery based on optimized CoMTA-C demonstrated fast kinetics and superior stability,with a low overpotential of 1.13 V,high specific capacity of 9057 mAh g^(-1),and long-term durability of 600 cycles.It provides a facile and effective strategy for enhancing the electrocatalytic performance through rational tuning of high-conductivity substances.展开更多
The distribution and source of the solvent-extractable organic and inorganic components in PM2.5 （aerodynamics equivalent diameter below 2.5 microns）, and PM10 （aerodynamics equivalent diameter below 10 microns） f...The distribution and source of the solvent-extractable organic and inorganic components in PM2.5 （aerodynamics equivalent diameter below 2.5 microns）, and PM10 （aerodynamics equivalent diameter below 10 microns） fractions of airborne particles were studied weekly from September 2006 to August 2007 in Beijing. The extracted organic and inorganic compounds identified in both particle size ranges consisted of n-alkanes, PAHs （polycyclic aromatic hydrocarbons）, fatty acids and water soluble ions. The potential emission sources of these organic compounds were reconciled by combining the values of n-alkane carbon preference index （CPI）, %waxCn, selected diagnostic ratios of PAHs and principal component analysis in both size ranges. The mean cumulative concentrations of n-alkanes reached 1128.65 ng/m3 in Beijing, 74% of which （i.e., 831.7 ng/m3） was in the PM2.5 fraction, PAHs reached 136.45 ng/m3 （113.44 ng/m3 or 83% in PM2.5）, and fatty acids reached 436.99 ng/m3 （324.41 ng/m3 or 74% in PM2.5）, which resulted in overall enrichment in the fine particles. The average concentrations of SO42-, NO3-, and NH4＋ were 21.3 ± 15.2, 6.1 ±1.8, 12.5 ± 6.1 μg/m3 in PM2.5, and 25.8±15.5, 8.9± 2.6, 16.9±9.5 μg/m3 in PM10, respectively. These three secondary ions primarily existed as ammonium sulfate （（NH4）2SO4）, ammonium bisulfate （NH4HSO4） and ammonium nitrate （NH4NO3）. The characteristic ratios of PAHs revealed that the primary sources of PAHs were coal combustion, followed by gasoline combustion. The ratios of stearic/palmitic acid indicated the major contribution of vehicle emissions to fatty acids in airborne particles. The major alkane sources were biogenic sources and fossil fuel combustion. The major sources of PAHs were vehicular emission and coal combustion.展开更多
The solvent extractable organic compounds （SEOC）, including n-alkanes, polycylic aromatic hydrocarbons, fatty acids, and dicarboxylic acids in PM2.5 during the 2007 Chinese Spring Festival in Beijing, were measured ...The solvent extractable organic compounds （SEOC）, including n-alkanes, polycylic aromatic hydrocarbons, fatty acids, and dicarboxylic acids in PM2.5 during the 2007 Chinese Spring Festival in Beijing, were measured via gas chromatography-mass spectrometry for determining the characteristics and sources of these organic pollutants. The concentrations of total n-alkanes, PAHs, and organic acids before Chinese Spring Festival Eve （1025.5, 95.9, and 543.3 ng/m3, respectively） were higher than those after （536.6, 58.9, and 331.8 ng/m3, respectively）, n-Aalkanes and PAHs had much higher concentration in nighttime than those in daytime because of high relative humidity and low wind speed during the night. Combustion of coal and exhaust emission were major sources of n- alkanes. It could be concluded by the characteristic ratios that the primary source of PAHs in fine particles was the combustion of coal, but the combustion of gasoline was in the next place. The ratios of C18：0/C16 indicated the contribution of vehicular emissions to the fatty acids. Dicarboxylic and aromatic acids were abundant in daytime than in nighttime because these acids were secondary organic acid and the photochemical degradation of aromatic hydrocarbons was the main source.展开更多
Hydrogen fuel cells are among the promising energy sources worldwide,which could accomplish cyclic production of energy and avoid the emission of green-house or contaminative byproducts.However,sulfur compounds(SCs)ev...Hydrogen fuel cells are among the promising energy sources worldwide,which could accomplish cyclic production of energy and avoid the emission of green-house or contaminative byproducts.However,sulfur compounds(SCs)even at trace level(nmol/mol)are usually involved in cell construction and further H_(2)production,which would cause degradation of the catalysts and shorten the lifetime of the fuel cells.Moreover,the highly reactive SCs could cause varied species and concentrations of them in complex matrices,so online rather than offline analysis of SCs in H_(2)would be preferred.In this context,we developed a new system combining online cryogenic preconcentration of nine SCs and subsequent determination by GC-SCD(sulfur chemiluminescent detector),with the correlation coefficients of the calibration curves higher than 0.999,calculated limits of detection no higher than 0.050 nmol/mol,analytical time around 30 min per sample,and satisfactory precision and accuracy(RSD<5%and SD<15%).The analytical performance was much better than or at least comparable to the previously reported and the developed system was successfully applied for real sample analysis.展开更多
Aluminum hypophosphite （AP） was used to prepare flame-retarded thermoplastic polyurethane （FR-TPU） composites, and their flame retardancy, thermal degradation and mechanical properties were investigated by limitin...Aluminum hypophosphite （AP） was used to prepare flame-retarded thermoplastic polyurethane （FR-TPU） composites, and their flame retardancy, thermal degradation and mechanical properties were investigated by limiting oxygen index （LOI）, vertical burning test （UL-94）, thermogravimetric analysis （TGA）, cone calorimeter （CC） test, Fourier transform infrared （FTIR） spectroscopy, scanning electron microscopy （SEM） and tensile test. TPU containing 30 wt% of AP could reach a V-0 rating in the UL-94 test, and its LOI value was 30.2. TGA tests revealed that AP enhanced the formation of residual chars at high temperatures, and slightly affected the thermal stability of TPU at high temperatures. The combustion tests indicated that AP affected the burning behavior of TPU. The peak of heat release rate （PHRR）, total heat release （THR） and mass loss rate （MLR） greatly reduced due to the incorporation of AP. The tensile test results showed that both the tensile strength and the elongation at break slightly decreased with the addition of AP. The digital photos and SEM micrographs vitrified that AP facilitated the formation of more compact intumescent char layer. Based on these results mentioned above, the flame-retarding mechanism of AP was discussed. Both the self-charring during the decomposing process of AP and its facilitation to the charring of TPU led to the great improvement in the flame retardancy of TPU.展开更多
Experiments were conducted to evaluate the potential for improving the mechanical properties of Mg-Al-Zn alloy at room temperature by subjecting to accumulative roll-bonding(ARB).It is shown that ARB may be applied su...Experiments were conducted to evaluate the potential for improving the mechanical properties of Mg-Al-Zn alloy at room temperature by subjecting to accumulative roll-bonding(ARB).It is shown that ARB may be applied successfully to Mg-Al-Zn alloy at elevated temperatures and it leads to grain refinement and significant improvements in the ductility.The strength of the as-rolled Mg-Al-Zn alloy sheet after ARB processing is slightly decreased and basal texture is weakened by ARB processing.展开更多
A TIA1N/MoS2-Ti coating was developed to improve the tribological characteristics of a single TiAlN coating. The MoS2-Ti layer was deposited by a DC magnetron sputtering system on the hard TiAIN coated SKD-11 steel su...A TIA1N/MoS2-Ti coating was developed to improve the tribological characteristics of a single TiAlN coating. The MoS2-Ti layer was deposited by a DC magnetron sputtering system on the hard TiAIN coated SKD-11 steel substrate. The titanium content in the MoS2-Ti layer was 11.3 at.% determined by EPMA. The surface morphology was observed by FE-SEM. The TiAlN layer exhibited excellent adhesion and hardness. However, the deposition of an MoS2-Zi layer on the TRAIN led to a significant improvement in tribological properties without affecting the adhesion to the substrate. The MoS2-Ti layer significantly decreased the friction coefficient of the TiAIN coating, and the drop was 48% after MoS2-Ti deposition. Also, the MoS2-Ti layer remarkably decreased the wear rate of the TtA1N coating.展开更多
Qualitative and quantitative analyses of derivatized phenols in Beijing and in Xinglong were performed from 2016 to 2017 using gas chromatography-mass spectrometry.The results showed substantially more severe pollutio...Qualitative and quantitative analyses of derivatized phenols in Beijing and in Xinglong were performed from 2016 to 2017 using gas chromatography-mass spectrometry.The results showed substantially more severe pollution in Beijing.Of the 14 compounds detected,the total average concentration was 100 ng/m^3 in Beijing,compared with 11.6 ng/m^3 in Xinglong.More specifically,concentration of nitro-aromatic compounds(NACs)(81.9 ng/m^3 in Beijing and 8.49 ng/m^3 in Xinglong) was the highest,followed by aromatic acids(14.6 ng/m^3 in Beijing and 2.42 ng/m^3 in Xinglong) and aromatic aldehydes(3.62 ng/m^3 in Beijing and 0.681 ng/m^3 in Xinglong).In terms of seasonal variation,the highest concentrations were found for 4-nitrocatechol in winter in Beijing(79.1±63.9 ng/m^3) and 4-nitrophenol in winter in Xinglong(9.72±8.94 ng/m^3).The analysis also revealed diurnal variations across different seasons.Most compounds presented higher concentrations at night in winter because of the decreased boundary layer height and increased heating intensity.While some presented higher levels during the day,which attributed to the photo-oxidation process for summer and more biomass burning activities for autumn.Higher concentrations appeared in winter and autumn than in spring and summer,which resulted from more coal combustions and adverse meteorological conditions.The significant correlations among NACs indicated similar sources of pollution.Higher correlations presented within each subgroup than those between the subgroups.Good correlations between levoglucosan and nitrophenols,nitrocatechols,nitro salicylic acids,with correlation coefficients(r) of 0.66,0.69 and 0.69,respectively,indicating an important role of biomass burning among primary sources.展开更多
基金the financial support from the National Natural Science Foundation of China(52203123 and 52473248)State Key Laboratory of Polymer Materials Engineering(sklpme2024-2-04)+1 种基金the Fundamental Research Funds for the Central Universitiessponsored by the Double First-Class Construction Funds of Sichuan University。
文摘Composite polymer electrolytes(CPEs)offer a promising solution for all-solid-state lithium-metal batteries(ASSLMBs).However,conventional nanofillers with Lewis-acid-base surfaces make limited contribution to improving the overall performance of CPEs due to their difficulty in achieving robust electrochemical and mechanical interfaces simultaneously.Here,by regulating the surface charge characteristics of halloysite nanotube(HNT),we propose a concept of lithium-ion dynamic interface(Li^(+)-DI)engineering in nano-charged CPE(NCCPE).Results show that the surface charge characteristics of HNTs fundamentally change the Li^(+)-DI,and thereof the mechanical and ion-conduction behaviors of the NCCPEs.Particularly,the HNTs with positively charged surface(HNTs+)lead to a higher Li^(+)transference number(0.86)than that of HNTs-(0.73),but a lower toughness(102.13 MJ m^(-3)for HNTs+and 159.69 MJ m^(-3)for HNTs-).Meanwhile,a strong interface compatibilization effect by Li^(+)is observed for especially the HNTs+-involved Li^(+)-DI,which improves the toughness by 2000%compared with the control.Moreover,HNTs+are more effective to weaken the Li^(+)-solvation strength and facilitate the formation of Li F-rich solid-electrolyte interphase of Li metal compared to HNTs-.The resultant Li|NCCPE|LiFePO4cell delivers a capacity of 144.9 m Ah g^(-1)after 400 cycles at 0.5 C and a capacity retention of 78.6%.This study provides deep insights into understanding the roles of surface charges of nanofillers in regulating the mechanical and electrochemical interfaces in ASSLMBs.
基金financially supported by the National Key R&D Program of China (No.2021YFA1200203)the National Natural Science Foundation of China (Nos.51922026 and 51975111)+1 种基金the Fundamental Research Funds for the Central Universities (No.N2202015,N2002005,and N2105001)the 111 Project of China (No.BP0719037 and B20029)。
文摘Face-centered cubic (f.c.c.) high entropy alloys (HEAs) are attracting more and more attention owing to their excellent strength and ductility synergy, irradiation resistance, etc. However, the yield strength of f.c.c. HEAs is generally low, significantly limiting their practical applications. Recently, the alloying of W has been evidenced to be able to remarkably improve the mechanical properties of f.c.c. HEAs and is becoming a hot topic in the community of HEAs. To date, when W is introduced, multiple strengthening mechanisms, including solid-solution strengthening, precipitation strengthening (μphase,σphase, and b.c.c. phase), and grain-refinement strengthening, have been discovered to be activated or enhanced. Apart from mechanical properties, the addition of W improves corrosion resistance as W helps to form a dense WO_(3) film on the alloy surface. Until now, despite the extensive studies in the literature, there is no available review paper focusing on the W doping of the f.c.c. HEAs. In that context, the effects of W doping on f.c.c. HEAs were reviewed in this work from three aspects, i.e., microstructure,mechanical property, and corrosion resistance. We expect this work can advance the application of the W alloying strategy in the f.c.c. HEAs.
基金supported by the National Natural Science Foundation of China(Nos.42171108 and 42101136)Sichuan Science and Technology Program(Nos.2024NSFSC2007 and2025YFHZ0273)Natural Science Starting Project of SWPU(No.2024QHZ029)。
文摘In cold regions,slope rocks are inevitably impacted by freeze-thaw,dry-wet cycles and their alternating actions,leading to strength weakening and pore degradation.In this study,the mechanical and microstructural properties of schist subjected to four conditions were investigated:freeze-thaw cycles in air(FTA),freeze-thaw cycles in water(FTW),dry-wet cycles(DW),and dry-wet-freeze-thaw cycles(DWFT).Uniaxial compressive strength(UCS),water absorption,ultrasonication,low-field nuclear magnetic resonance,and scanning electron microscopy analyses were conducted.The integrity attenuation characteristics of the longitudinal wave velocity,UCS,and elastic modulus were analyzed.The results showed that liquid water emerged as a critical factor in reducing the brittleness of schist.The attenuation function model accurately described the peak stress and static elastic modulus of schist in various media(R2>0.97).Different media affected the schist deterioration and half-life,with the FTW-immersed samples having a half-life of 28 cycles.Furthermore,the longitudinal wave velocity decreased as the number of cycles increased,with the FTW showing the most significant reduction and having the shortest half-life of 208 cycles.Moreover,the damage variables of compressive strength and elastic modulus increased with the number of cycles.After 40 cycles,the schist exposed to FTW exhibited the highest damage variables and saturated water content.
文摘To achieve efficient catalytic hydrogenation of CO_(2)to formate,we employed a transmetallation strategy to develop three novel iridium(Ⅰ)complexes,which feature N‑heterocyclic carbene‑nitrogen‑phosphine ligands(CNP)and a 1,5‑cyclooctadiene(cod)molecule:[Ir(cod)(κ^(3)‑CN^(im)P)]Cl(1⁃Cl),[Ir(cod)(κ^(3)‑CN^(im)P)]PF6(1⁃PF_(6)),and[Ir(cod)(κ^(3)‑CNHP)]Cl(2).The^(1)H NMR spectra,^(31)P NMR spectra,and high‑resolution mass spectra verify the successful synthesis of these three Ir(Ⅰ)‑CNP complexes.Furthermore,single‑crystal X‑ray diffraction analysis confirms the coordination geometry of 1⁃PF_(6).The strong Ir—C(NHC)bond suggests that the carbene carbon plays an enhanced anchoring role to iridium due to its strongσ‑donating ability,which helps stabilize the active metal species during CO_(2)hydrogenation.As a result,the Ir(Ⅰ)‑CNP complex exhibits remarkable activity and long catalytic lifetime for the hydrogenation of CO_(2)to formate,reaching a turnover number(TON)of 1.16×10^(6)after 150 h at a high temperature of 170℃,which was a relatively high value among all the Ir complexes.CCDC:2384071,1⁃PF_(6).
基金Supported by the Joint Funds of the National Natural Science Foundation of China(U2340219)。
文摘Cadmium(Cd)or excess copper(Cu)has a great impact in terms of toxicity on living organisms as it severely affects crop growth,yield and food security;thus,warranting appropriate measures for the remediation of Cd or Cu polluted soils.Phytoextraction of heavy metal(HM)using tolerant plants along with organic chelators has gained global attention,and this study provided further insights into this issue.Pot experiments were performed to evaluate the effects of different types of chelators[ethylenediamine tetraacetic acid(EDTA),ethylenediamine disuccinic acid(EDDS)and citric acid(CA)]to improve the phytoextraction capacity of Ricinus communis L.for the metals Cd and Cu.Contaminated soil from a copper smelter was used in this study.A rhizon soil sampler was used to determine the metal concentrations in soil pore water.The results indicated that R.communis was an adequate candidate for chelator induced phytoextraction under the experimental conditions and that EDDS would be a good candidate chelator for the phytoextraction of Cu in soils.EDTA addition obviously improved the uptake of Cd and Cu in R.communis;however,it posed the greatest risk because the concentration of HMs in soil pore water was very high even after 40 days.Compared with EDTA and EDDS,CA had few effects on Cd or Cu uptake in R.communis.Linear relationships between the metal uptake in R.communis shoots and the maximum HM concentrations in soil pore water under HM,2.5,5,and 10 mmol·kg^(-1) treatments were typically observed.From the results of this study,it could be concluded that EDDS treatments played a promising role in increasing the uptake of Cd or Cu and reducing its phytotoxicity.EDDS application could be an effective approach for the phytoextraction of Cd or Cu from polluted soils by growing Ricinus communis L.
基金financial assistance from the Anhui Provincial Major Science and Technology Project(202003a05020022)the Institute of Energy,Hefei Comprehensive National Science Center(21KZS219)。
文摘The direct oxidation of methane to methanol(DOMM) has been recognized as a significant technology for efficiently utilizing low-concentration coalbed methane(LCMM) and supplying liquid fuel.Herein,the noble metals(Pt,Pd and Ru) modified Cu/alkalized sepiolite(CuX/SEPA) catalysts were prepared and used for the DOMM in a gas-phase system at low temperatures.The CuRu/SEPA exhibited the highest methanol production of 53 μmol·g^(-1)·h^(-1) and methanol selectivity of 90% under the optimal reaction conditions.Various characterizations demonstrated that the addition of Ru promoted the formation of Cu^(2+)and the contraction of Cu—Si/Al bonds to reduce the distance between framework Al atoms of SEPA to further generate more Al pairs,which facilitated the formation of reactive dicopper species([Cu_(2)O]^(2+)or [Cu_(2)O_(2)]^(2+)).Investigation of the reaction mechanism revealed that [Cu_(2)O]^(2+) or [Cu_(2)O_(2)]^(2+) species could adsorb and activate methane to form CH_(3)O^(*) species and ultimately generated methanol with the assistance of water.
基金financially supported by the National Natural Science Foundation of China(Nos.52125103,52371212,52071041,12204080,12374002)the Scientific and Technological Research Program of Chongqing Municipal Education Commission(Nos.KJQN202400604,KJQN202200623,KJZD-K202100602)+1 种基金the Fundamental Research Funds for the Central Universities(Nos.2024IAIS-ZX002,2023CDJKYJH006)the Natural Science Foundation of Chongqing(No.CSTB2022NSCQ-MSX0382).
文摘SnSe_(2) single crystals,as novel n-type plastic thermoelectric materials,present advantages such as envi-ronmental sustainability and cost-effectiveness.Single crystals of SnSe_(2)+x%PbBr_(2)(x=0,0.5,1,2,and 3)with large size and high quality were successfully synthesized via the Bridgman method.The significant enhancement in power factor and effective suppression of lattice thermal conductivity can be achieved through PbBr_(2) doping,verifying a synergistic optimization of electrical and thermal transport properties.Specifically,Br atoms are effectively incorporated into the Se sites to manipulate the carrier concentra-tion and optimize the power factor,while simultaneously inducing a strong phonon softening effect by introducing Pb atoms at the Sn sites,which leads to a reduced phonon group velocity and a suppres-sion of lattice thermal conductivity.Consequently,SnSe_(2)+2%PbBr_(2) single-crystal sample achieves a peak figure of merit zT of~0.76 and an average zT of~0.51,giving rise to corresponding improvements of~533% and~538%,respectively,compared to the pristine SnSe_(2) sample,thereby outperforming most of the previously reported SnSe_(2)-based materials.This work provides a viable approach for promoting the thermoelectric performance of SnSe^(2)-based single crystals across a broad temperature range and supports the advancement of plastic thermoelectric materials.
文摘Correction to:Rare Met.https://doi.org/10.1007/s12598-021-01815-z In the original publication,Fig.5 was published with few mistakes.The correct version of Fig.5 is given in this correction.
基金supported by the National Natural Science Foundation of China under Grant Nos.12102310 and U21A20113the Guangdong Basic and Applied Basic Research Foundation under Grant No.2020A1515110818+2 种基金the Inovation Team Project for Colleges and Universities of Guangdong Province under Grant No.2023KCXTD030the Key Project of Biomedicine and Health in Colleges and Universities of Guangdong Province under Grant No.2021ZDZX2055the Medical Science and Technology Research Fund of Guangdong Province under Grant No.A2022004.
文摘Proton exchange membrane fuel cells(PEMFCs)have gained increasing interests as promising power sources due to their ability to convert hydrogen and oxygen directly into electricity with high efficiency and zero greenhouse gas emissions.Bipolar plates(BPs)are considered as a critical component of PEMFCs,serving to collect current,separate gases,distribute the flow field,and conduct heat.This paper reviews the technical status and advancements in BP materials,with special focus on strategies for enhancing interfacial contact resistance(ICR)and corrosion resistance through conductive polymer(CP)coatings.First,commonly used BP materials in PEMFCs are summarized.Then,the advantages and limitations of various coatings for metallic BPs are discussed.Finally,recent progress in CP coatings for metallic BPs,aimed at achieving high corrosion resistance and low ICR,is comprehensively reviewed.
基金Supported by the Hainan Province Science and Technology Special Fund (No.ZDYF2022SHFZ317)the Guangdong Province Key Laboratory of Applied Marine Biology (No.2023B1212060047)the Program for Scientific Research Start-up Funds of Guangdong Ocean University (No.060302332301)。
文摘Expanded polystyrene (EPS) is a common type of microplastics (MPs) often found in coastal areas especially aquaculture areas.It is considered as an important site for microbial colonization and biofilm formation,as well as a carrier of pollutants like heavy metals.However,the dynamic changes of bacterial communities attached to EPS and their interaction with heavy metals are still poorly unknown.In this study,a one-year field exposure experiment was conducted at an aquaculture farm near Donghai Island,in Leizhou Bay,Zhanjiang,Guangdong,in South China Sea.The bacterial communities attached to EPS MPs were examined by 16S r DNA high-throughput sequencing,and the relationships between bacterial biofilms and heavy metals were explored.The results show that there were notable seasonal variations in the bacterial diversity of EPS MPs.Species biodiversity was the highest in summer and the lowest in winter.The greatest number of bacterial species and lowest level of uniformity were observed in the spring.The bacterial community structure changed with exposure time,and the most significant difference in the 12-month group (P<0.05) was found.The dominant bacterial species attached to EPS MPs were mainly Proteobackteria and Firmicutes at the phylum level,and Pseudomonas and Exiguobacterium were dominant at the genus level.Furthermore,EPS MPs acted as transport carriers for potential pathogenic bacteria.High correlations were found between bacterial species and the total concentration of heavy metals on EPS MPs,as well as their speciation fractions.Different chemical speciation of heavy metals migrated and altered over seasons within biofilms,which would further exacerbate the ecological risks.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.U21A2057 and U1908223)the open research fund for the State Key Laboratory of Advanced Refractories(Grant No.SKLAR202405).
文摘Alkaline slag is vital in rare earth steel refining,making it crucial to study the wetting and penetration mechanisms between refractory materials and slag.The effect of Eu_(2)O_(3) doping on the sintering properties of MgO-MgAl_(2)O_(4) refractory materials was investigated while simulating the wetting behavior between the refractory and the CaO-Al_(2)O_(3)-SiO_(2)-MgO quaternary alkaline slag during rare earth steel smelting to improve the material’s resistance to alkaline slag corrosion.The doping of Eu_(2)O_(3) can alter the crystal structure parameters of MgAl_(2)O_(4) and MgO,causing lattice distortion.This lattice activation promotes interionic mass and diffusion,helping reduce porosity and promote densification of the material,further improving sintering properties.At the equilibrium wetting temperature(1723 K),Eu_(2)O_(3) doping increases the interfacial free energy between the slag and refractory material,reducing the spreading coefficient of the molten slag.The contact angle increases from 32.1°to 42.2°,and the residual slag volume increases from 17.9%to 23.5%.The results of thermodynamic analysis show that MgAl_(2)O_(4) and EuAlO3 formed at the interface block the penetration of molten slag at high temperatures,improving the resistance of MgO-MgAl_(2)O_(4) refractories to alkaline slag corrosion.Based on the capillary theory model,it was calculated that the capillary tension of the slag gradually increases with the addition of Eu_(2)O_(3),while the theoretical penetration depth of the slag gradually decreases.The experimental results showed that the slag erosion depth of the sample decreased from 102.54 to 68.28μm.
基金the National Natural Science Foundation of China(U21A2057)the Natural Science Foundation of Chongqing(No.cstc2021jcyj-msxmX1139)the Science and Technology Research Program of Chongqing Municipal Education Commission(Nos.KJZD-M202301201 and KJZD-K202304502).
文摘To improve the practical application of carbon steel,developing a superhydrophobic coating with outstanding mechanical properties is essential for effective corrosion resistance protection.Here,we obtained a robust superhydrophobic anti-corrosion coating with a cauliflower structure by co-depositing the lauric acid with Ni ions and Mn ions onto a carbon steel through electrodeposition method.As demonstrated by the results,superhydrophobic Ni/Mn alloy(SNMAmit)displays a multi-hierarchical micro/nano cauliflower structure under the synergy of optimal parameters,exhibiting superb superhydrophobicity with contact angle of 161.9°and sliding angle of 6.2°.Surprisingly,the Tafel polarization curves in 3.5%NaCl showed that the corrosion potential of SNMAmit coating was 476 mV,and the corrosion current density was reduced from 1.39×10^(−5)to 5.89×10^(−7)A/cm^(2).The reduced corrosion current density of superhydrophobic Ni/Mn alloy(SNMA)indicates that SNMA coating can significantly enhance the anti-corrosion properties of carbon steel.In addition,after being subjected to various damages such as blade scraping,tape cyclic peeling,acid and alkalis,sandpaper cyclic abrasion,high temperatures,ultrasound,and graphite contaminant,SNMA showed good mechanical stability,interference resistance,heat resistance,and self-cleaning properties,which made it suitable for hostile conditions.
基金financially supported by the National Natural Science Foundations of China(No.12304037)the Interdisciplinary Intelligence Super Computer Center of BNUZH
文摘The metal triazole(MTA)-based MOFs were found to preferentially adsorb O-rich species,which had enhanced electrocatalytic oxygen reduction reactions(ORR)and stabilized the O-containing species during the discharge and charge processes in Li-O_(2)battery.However,the MOFs exhibited low electron conductivity and poor electron transfer interface in the electrocatalysis,limiting the electrocatalytic activity.To address this issue,a nanocomposite with the Co-MTA-coated carbon nano tubes(Co-MTA-C)was constructed,which formed the three-dimensional conductivity network connected with the intersecting carbon nano tube(CNT).In this composite,the electron-rich Co-MTA interacted with the highly conductive CNT,resulting in a charge redistribution.Optimized the electronic structure of the Co center through compositional modifications presented a high valence compared to the pure MOFs.In situ X-ray absorption spectroscopy revealed a direct reaction of Co sites with intermediates such as LiO_(x),leading to the formation of nanosheet array discharge products.The battery based on optimized CoMTA-C demonstrated fast kinetics and superior stability,with a low overpotential of 1.13 V,high specific capacity of 9057 mAh g^(-1),and long-term durability of 600 cycles.It provides a facile and effective strategy for enhancing the electrocatalytic performance through rational tuning of high-conductivity substances.
基金supported by the Science and Technology Project of Beijing (No. D09040903670902)the Chinese Academy of Sciences for Key Topics in Innovation Engineering (No. KZCX2-YW-Q02-03)the Basic Research and Development Program (973) of China (No.2007CB407303)
文摘The distribution and source of the solvent-extractable organic and inorganic components in PM2.5 （aerodynamics equivalent diameter below 2.5 microns）, and PM10 （aerodynamics equivalent diameter below 10 microns） fractions of airborne particles were studied weekly from September 2006 to August 2007 in Beijing. The extracted organic and inorganic compounds identified in both particle size ranges consisted of n-alkanes, PAHs （polycyclic aromatic hydrocarbons）, fatty acids and water soluble ions. The potential emission sources of these organic compounds were reconciled by combining the values of n-alkane carbon preference index （CPI）, %waxCn, selected diagnostic ratios of PAHs and principal component analysis in both size ranges. The mean cumulative concentrations of n-alkanes reached 1128.65 ng/m3 in Beijing, 74% of which （i.e., 831.7 ng/m3） was in the PM2.5 fraction, PAHs reached 136.45 ng/m3 （113.44 ng/m3 or 83% in PM2.5）, and fatty acids reached 436.99 ng/m3 （324.41 ng/m3 or 74% in PM2.5）, which resulted in overall enrichment in the fine particles. The average concentrations of SO42-, NO3-, and NH4＋ were 21.3 ± 15.2, 6.1 ±1.8, 12.5 ± 6.1 μg/m3 in PM2.5, and 25.8±15.5, 8.9± 2.6, 16.9±9.5 μg/m3 in PM10, respectively. These three secondary ions primarily existed as ammonium sulfate （（NH4）2SO4）, ammonium bisulfate （NH4HSO4） and ammonium nitrate （NH4NO3）. The characteristic ratios of PAHs revealed that the primary sources of PAHs were coal combustion, followed by gasoline combustion. The ratios of stearic/palmitic acid indicated the major contribution of vehicle emissions to fatty acids in airborne particles. The major alkane sources were biogenic sources and fossil fuel combustion. The major sources of PAHs were vehicular emission and coal combustion.
基金supported by the National Basic Re-search Program (973) of China (No. 2007CB407303)the National Natural Science Foundation of China (No.40525016)the Hi-Tech Research and Development Program (863) of China (No. 2006AA06A301).
文摘The solvent extractable organic compounds （SEOC）, including n-alkanes, polycylic aromatic hydrocarbons, fatty acids, and dicarboxylic acids in PM2.5 during the 2007 Chinese Spring Festival in Beijing, were measured via gas chromatography-mass spectrometry for determining the characteristics and sources of these organic pollutants. The concentrations of total n-alkanes, PAHs, and organic acids before Chinese Spring Festival Eve （1025.5, 95.9, and 543.3 ng/m3, respectively） were higher than those after （536.6, 58.9, and 331.8 ng/m3, respectively）, n-Aalkanes and PAHs had much higher concentration in nighttime than those in daytime because of high relative humidity and low wind speed during the night. Combustion of coal and exhaust emission were major sources of n- alkanes. It could be concluded by the characteristic ratios that the primary source of PAHs in fine particles was the combustion of coal, but the combustion of gasoline was in the next place. The ratios of C18：0/C16 indicated the contribution of vehicular emissions to the fatty acids. Dicarboxylic and aromatic acids were abundant in daytime than in nighttime because these acids were secondary organic acid and the photochemical degradation of aromatic hydrocarbons was the main source.
基金the financial support to this work by Sichuan Science and Technology,China(Nos.2019ZDZX0035&2018TZDZX0008)the Ministry of Education through the 111 Project(No.B17030).
文摘Hydrogen fuel cells are among the promising energy sources worldwide,which could accomplish cyclic production of energy and avoid the emission of green-house or contaminative byproducts.However,sulfur compounds(SCs)even at trace level(nmol/mol)are usually involved in cell construction and further H_(2)production,which would cause degradation of the catalysts and shorten the lifetime of the fuel cells.Moreover,the highly reactive SCs could cause varied species and concentrations of them in complex matrices,so online rather than offline analysis of SCs in H_(2)would be preferred.In this context,we developed a new system combining online cryogenic preconcentration of nine SCs and subsequent determination by GC-SCD(sulfur chemiluminescent detector),with the correlation coefficients of the calibration curves higher than 0.999,calculated limits of detection no higher than 0.050 nmol/mol,analytical time around 30 min per sample,and satisfactory precision and accuracy(RSD<5%and SD<15%).The analytical performance was much better than or at least comparable to the previously reported and the developed system was successfully applied for real sample analysis.
基金financially supported by the National Natural Science Foundation of China(Nos.50933005 and 51121001)the Program for Changjiang Scholars and Innovative Research Teams in Universities of China(IRT 1026)
文摘Aluminum hypophosphite （AP） was used to prepare flame-retarded thermoplastic polyurethane （FR-TPU） composites, and their flame retardancy, thermal degradation and mechanical properties were investigated by limiting oxygen index （LOI）, vertical burning test （UL-94）, thermogravimetric analysis （TGA）, cone calorimeter （CC） test, Fourier transform infrared （FTIR） spectroscopy, scanning electron microscopy （SEM） and tensile test. TPU containing 30 wt% of AP could reach a V-0 rating in the UL-94 test, and its LOI value was 30.2. TGA tests revealed that AP enhanced the formation of residual chars at high temperatures, and slightly affected the thermal stability of TPU at high temperatures. The combustion tests indicated that AP affected the burning behavior of TPU. The peak of heat release rate （PHRR）, total heat release （THR） and mass loss rate （MLR） greatly reduced due to the incorporation of AP. The tensile test results showed that both the tensile strength and the elongation at break slightly decreased with the addition of AP. The digital photos and SEM micrographs vitrified that AP facilitated the formation of more compact intumescent char layer. Based on these results mentioned above, the flame-retarding mechanism of AP was discussed. Both the self-charring during the decomposing process of AP and its facilitation to the charring of TPU led to the great improvement in the flame retardancy of TPU.
基金Project(36547)supported by the Natural Science Foundation of Guangdong Province,ChinaProject(2007001)supported by PublicFoundation of Guangdong Key Laboratory for Advanced Metallic Materials Processing,South China University of Technology,China
文摘Experiments were conducted to evaluate the potential for improving the mechanical properties of Mg-Al-Zn alloy at room temperature by subjecting to accumulative roll-bonding(ARB).It is shown that ARB may be applied successfully to Mg-Al-Zn alloy at elevated temperatures and it leads to grain refinement and significant improvements in the ductility.The strength of the as-rolled Mg-Al-Zn alloy sheet after ARB processing is slightly decreased and basal texture is weakened by ARB processing.
文摘A TIA1N/MoS2-Ti coating was developed to improve the tribological characteristics of a single TiAlN coating. The MoS2-Ti layer was deposited by a DC magnetron sputtering system on the hard TiAIN coated SKD-11 steel substrate. The titanium content in the MoS2-Ti layer was 11.3 at.% determined by EPMA. The surface morphology was observed by FE-SEM. The TiAlN layer exhibited excellent adhesion and hardness. However, the deposition of an MoS2-Zi layer on the TRAIN led to a significant improvement in tribological properties without affecting the adhesion to the substrate. The MoS2-Ti layer significantly decreased the friction coefficient of the TiAIN coating, and the drop was 48% after MoS2-Ti deposition. Also, the MoS2-Ti layer remarkably decreased the wear rate of the TtA1N coating.
基金supported by the National Key R&D Program of China (No:2017YFC0210000)the Ministry of Science and Technology of China (No:2016YFC0202001).
文摘Qualitative and quantitative analyses of derivatized phenols in Beijing and in Xinglong were performed from 2016 to 2017 using gas chromatography-mass spectrometry.The results showed substantially more severe pollution in Beijing.Of the 14 compounds detected,the total average concentration was 100 ng/m^3 in Beijing,compared with 11.6 ng/m^3 in Xinglong.More specifically,concentration of nitro-aromatic compounds(NACs)(81.9 ng/m^3 in Beijing and 8.49 ng/m^3 in Xinglong) was the highest,followed by aromatic acids(14.6 ng/m^3 in Beijing and 2.42 ng/m^3 in Xinglong) and aromatic aldehydes(3.62 ng/m^3 in Beijing and 0.681 ng/m^3 in Xinglong).In terms of seasonal variation,the highest concentrations were found for 4-nitrocatechol in winter in Beijing(79.1±63.9 ng/m^3) and 4-nitrophenol in winter in Xinglong(9.72±8.94 ng/m^3).The analysis also revealed diurnal variations across different seasons.Most compounds presented higher concentrations at night in winter because of the decreased boundary layer height and increased heating intensity.While some presented higher levels during the day,which attributed to the photo-oxidation process for summer and more biomass burning activities for autumn.Higher concentrations appeared in winter and autumn than in spring and summer,which resulted from more coal combustions and adverse meteorological conditions.The significant correlations among NACs indicated similar sources of pollution.Higher correlations presented within each subgroup than those between the subgroups.Good correlations between levoglucosan and nitrophenols,nitrocatechols,nitro salicylic acids,with correlation coefficients(r) of 0.66,0.69 and 0.69,respectively,indicating an important role of biomass burning among primary sources.
