Efficient lubrication of magnesium alloys is a highly challenging topic in the field of tribology.In this study,magnesium silicate hydroxide(MSH)nanotubes with serpentine structures were synthesized.The tribological b...Efficient lubrication of magnesium alloys is a highly challenging topic in the field of tribology.In this study,magnesium silicate hydroxide(MSH)nanotubes with serpentine structures were synthesized.The tribological behavior of AZ91D magnesium alloy rubbed against GCr15 steel was studied under lubricating oil with surface-modified MSH nanotubes as additives.The effects of the concentration,applied load,and reciprocating frequency on the friction and wear of the AZ91D alloy were studied using an SRV-4 sliding wear tester.Results show a decrease of 18.7–68.5%in friction coefficient,and a reduction of 19.4–54.3%in wear volume of magnesium alloy can be achieved by applying the synthetic serpentine additive under different conditions.A suspension containing 0.3 wt.%MSH was most efficient in reducing wear and friction.High frequency and medium load were more conducive to improving the tribological properties of magnesium alloys.A series of beneficial physical and chemical processes occurring at the AZ91D alloy/steel interface can be used to explain friction and wear reduction based on the characterization of the morphology,chemical composition,chemical state,microstructure,and nanomechanical properties of the worn surface.The synthetic MSH,with serpentine structure and nanotube morphology,possesses excellent adsorbability,high chemical activity,and good self-lubrication and catalytic activity.Therefore,physical polishing,tribochemical reactions,and physicalchemical depositions can occur easily on the sliding contacts.A dense tribolayer with a complex composition and composite structure was formed on the worn surface.Its high hardness,good toughness and plasticity,and prominent lubricity resulted in the improvement of friction and wear,making the synthetic MSH a promising efficient oil additive for magnesium alloys under boundary and mixed lubrication.展开更多
This study aims to develop a chloride diffusion simulation method that considers the hydration microstructure and pore solution properties during the hydration of tricalcium silicate(C3S).The method combines the hydra...This study aims to develop a chloride diffusion simulation method that considers the hydration microstructure and pore solution properties during the hydration of tricalcium silicate(C3S).The method combines the hydration simulation,thermodynamic calculation,and finite element analysis to examine the effects of pore solution,including effect of electrochemical potential,effect of chemical activity,and effect of mechanical interactions between ions,on the chloride effective diffusion coefficient of hydrated C3S paste.The results indicate that the effect of electrochemical potential on chloride diffusion becomes stronger with increasing hydration age due to the increase in the content of hydrated calcium silicate;as the hydration age increases,the effect of chemical activity on chloride diffusion weakens when the number of diffusible elements decreases;the effect of mechanical interactions between ions on chloride diffusion decreases with the increase of hydration age.展开更多
Sm^(3+)-doped materials exhibit red and orange emissions in the visible light region,showing broad applica⁃tion prospects in both laser and display material fields.However,the inherent small emission and absorption cr...Sm^(3+)-doped materials exhibit red and orange emissions in the visible light region,showing broad applica⁃tion prospects in both laser and display material fields.However,the inherent small emission and absorption cross-sections of Sm^(3+)result in low luminous efficiency,posing challenges for achieving high-quality solid-state lighting.Here,the excellent white emission of Sm^(3+)doped lithium aluminum silicate(LAS)glass was realized by introducing the Ag aggregates through Ag ion exchange.Under 395 nm excitation,the Ag-doped samples exhibit significant fluo⁃rescence enhancement with color coordinates close to the equal energy white point E(0.33,0.33)and a color ren⁃dering index(CRI)of 81.8.The study reveals that the surface plasmon resonance(SPR)effect of Ag nanoparticles enhances the luminescence of Sm^(3+),while the energy transfer mechanism between Ag^(+)and Sm^(3+)also promotes fluores⁃cence enhancement.By adjusting the concentration of AgNO_(3) and the exchange time,a series of high-quality full-spectrum white light emissions were obtained,indicating that the Ag ion-exchanged Sm^(3+)-doped LAS glass has good application potential in the development of solid-state lighting devices.Moreover,variations in the excitation wave⁃length can effectively tune the emission color,further demonstrating the tunability and practicality of this material in optoelectronic applications.展开更多
A novel method for scandium recovery is proposed through high-surface area silanol-rich silica sorbents which were prepared with calcium silicate hydrate(C-S-H) as raw material.Two types of silanol-rich silica particl...A novel method for scandium recovery is proposed through high-surface area silanol-rich silica sorbents which were prepared with calcium silicate hydrate(C-S-H) as raw material.Two types of silanol-rich silica particles,i.e.,LAC-S(silica derived from acid leaching of amorphous C-S-H) and LLC-S(silica derived from acid leaching of low-crystallinity C-S-H) are obtained after calcium ions are removed from both amorphous and low-crystallinity forms of C-S-H through a facile acid leaching process(3 mol/L,25℃,24 h).(29)^Si NMR spectroscopy reveals that the proportion of silicon atoms carrying silanol groups increases from less than 43% to over 80% when silica particles are transferred from a dry state to an aqueous solution.Batch adsorption experiments were conducted to evaluate the sorption performance and selectivity of these silica sorbents toward Sc(Ⅲ).The scandium sorption capacities of LAC-S and LLC-S at an equilibrium pH of 4.2 are 174.45 and 129.57 mg/g,respectively.The separation factors(SFSc/Ln) of both silica particles exceed 1000 in the initial pH range of 3.5-5.The loaded scandium ions are recovered with 3 mol/L hydrochloric acid and the sorbents exhibit good reusability.This strategy provides an efficient and green method for recovering scandium from aqueous solutions.展开更多
An in-depth understanding of the hydration mechanism of tricalcium silicate is an important basis for optimizing cement strength development.In this study,the adsorption of water molecules onto the M3-C3S(001)surface ...An in-depth understanding of the hydration mechanism of tricalcium silicate is an important basis for optimizing cement strength development.In this study,the adsorption of water molecules onto the M3-C3S(001)surface at different water coverage levels(θ=1/5,2/5,3/5,4/5,and 1)was investigated using first-principles calculations.The results demonstrate that the conclusions obtained for single water molecule adsorption cannot be fully applied to multiple water molecule adsorption.The total adsorption energies become more negative with increasing water coverage,while the average adsorption energy of each water molecule becomes more positive with increasing water coverage.The water–water interactions reduce the water–surface interactions and are responsible for the anticooperative adsorption of multiple water molecules onto M3-C_(3)S(001).The formation of Ca–OH(–Ca)bonds favors the detachment of Ca from co-valent oxygen,which reveals the significant role of dissociative adsorption.This work aims to extend the water adsorption study on M3-C3S(001)from single water molecule adsorption to multiple water molecule adsorption,providing more detailed insights into the initial water reaction on the C3S surface.展开更多
Aqueous zinc-based energy storage systems offer high theoretical specific capacity,low cost,intrinsic safety,and environmental compatibility,positioning them as promising candidates for next-generation energy storage ...Aqueous zinc-based energy storage systems offer high theoretical specific capacity,low cost,intrinsic safety,and environmental compatibility,positioning them as promising candidates for next-generation energy storage and conversion technologies.However,issues such as zinc dendrite growth,hydrogen evolution reaction(HER),and surface passivation hinder their practical deployment.To address these challenges,a hollow nanotubular magnesium silicate(denoted MgSi)interfacial layer was constructed on the zinc metal anode(Zn@MgSi).The unique layer structure and negatively charged surface of MgSi facilitate the desolvation of[Zn(H_(2)O)_(6)]^(2+)by stripping water molecules,while temporarily immobilizing Zn^(2+)to suppress random diffusion.The combined effects of the electric field-guided Zn^(2+)distribution and rapid ion transport through the layer structure co-regulate Zn^(2+)flux,leading to uniform,dendrite-free zinc deposition.Consequently,the Zn@MgSi symmetric cell demonstrates a high Zn^(2+)transference number(0.64),extended cycling life exceeding 1600 h at 1 mA cm^(−2),and stable operation for 200 h at 5 mA cm^(−2).Furthermore,zinc-ion hybrid capacitors employing Zn@MgSi electrodes exhibit excellent cycling stability over 5000 cycles.This work highlights the efficacy of artificial interfacial layers in stabilizing zinc metal anodes and provides valuable insights into the development of advanced aqueous zinc-ion energy storage systems.展开更多
Heavy metal-contaminated sites are primarily treated via solidification and adsorption.Calcium silicate hydrate(C-S-H)is generated during the soil stabilization process and contributes significantly to the strength an...Heavy metal-contaminated sites are primarily treated via solidification and adsorption.Calcium silicate hydrate(C-S-H)is generated during the soil stabilization process and contributes significantly to the strength and durability of the stabilized soil.To understand how the soil moisture content and heavy metal concentration affect the transport of heavy metals and the tensile strength of C-S-H,this study performed molecular dynamics(MD)simulations under different moisture and concentration levels.The results showed that Pb2+presented the highest adsorption to the surface of C-S-H due to its strong electrostatic interaction energy.The adsorption density peaks of Pb2+were 1.5–5 times greater than those of Cd2+and Zn2+.Zn2+and Cd2+ions were more likely to be adsorbed onto water molecules and form a larger hydrated radius than Pb2+.The adsorption of heavy metals onto C-S-H initially increased as the metal concentration increased and then decreased because of the limited sorption sites on C-S-H.The diffusion coefficients of the multicomponent metals in C-S-H showed no consistent trends.The maximum tensile strength of C-S-H decreased with increasing soil moisture and heavy metal concentrations.The tensile stress increased approximately linearly with strain until it reached a peak,after which it gradually declined but remained above zero,indicating good ductility and toughness under unsaturated conditions.These findings offer valuable molecular insights into the interactions between C-S-H and heavy metals and soil moisture,thereby advancing our understanding of their combined effects on soil stabilization.展开更多
The emission wavelength of current near-infrared phosphors activated by Cr^(3+)is generally smaller than 900 nm in near-infrared(NIR)Ⅰ region,and it is extremely challenging and is of great practical significance to ...The emission wavelength of current near-infrared phosphors activated by Cr^(3+)is generally smaller than 900 nm in near-infrared(NIR)Ⅰ region,and it is extremely challenging and is of great practical significance to realize emission towards NIR-Ⅱ region.In this study,a novel Cr^(3+)excited KSrScSi_(2)O_(7)silicate broad-band phosphor was prepared using the traditional solid-state method.Cr^(3+)resides in a weak crystal field in the KSrScSi_(2)O_(7)lattice and exhibits broad-band near-infrared emission at 984 nm,longer than those of most Cr^(3+)activated phosphors,under 493 nm blue light excitation.This is due to the stro ng charge polarization caused by the unique local coordination environment of the silicate matrix,which leads to a reduction in the crystal field splitting energy of the[ScO_(6)]octahedron where Cr^(3+)is located and the downward shift of the^(4)T_(2)energy level.The optimal doping concentration of Cr^(3+)is found to be 2 mol%,and the quenching mechanism is dipole-dipole interaction.Compared to the phosphors with similar emission wavelengths(λ_(em)>900 nm),KSrScSi_(2)O_(7):Cr^(3+)demonstrates outstanding advantages in various aspects of luminescent performance.The fabricated phosphor-converted light-emitting diode(pc-LED)is shown to have the potential for night vision and non-invasive imaging.Novel application of KSrScSi_(2)O_(7):xCr^(3+)as stable green ceramic pigments is also explored.The KSrScSi_(2)O_(7):xCr^(3+)powders show a bright yellowish green appearance,and the KSrScSi_(2)O_(7):0.02Cr^(3+)typical composition has chromaticity values of L^(*)=82.73,a^(*)=-8.53,b^(*)=7.97.Remarkably,the glazing samples using KSrScSi_(2)O_(7):xCr^(3+)as pigments well retain the bright color after 1200℃sintering in different atmospheres.Therefore,multifunctional applications of KSrScSi_(2)O_(7):xCr^(3+)for near-infrared spectroscopy and as ceramic pigments are achieved in this work.展开更多
The paper overviews the research and application of silicate plugging agent, according to the different mechanisms and application forms, the plugging agent is divided into silicate gel, silicate precipitation, silica...The paper overviews the research and application of silicate plugging agent, according to the different mechanisms and application forms, the plugging agent is divided into silicate gel, silicate precipitation, silicate/polymer, silicate/surfactant, silicate gel/foam and so on. This paper chiefly introduces the conception, mechanism and development tendency of the different systems mentioned above. The development tendency manifests as fully utilize personal properties and cooperate with other plugging agents or technologies, including the study of reaction mechanism, combination of plugging agent, grasping water flood timing, developing deep profile control and water shutoff technology, combining with other measures (chemicals huff and puff), in order to play the role of such blocking agents, further enhance oil recovery.展开更多
The leaching kinetics of zinc silicate in ammonium chloride solution was investigated. The effects of stirring speed （150？400 r/min）, leaching temperature （95-108 ℃, particle size of zinc silicate （61-150 μm...The leaching kinetics of zinc silicate in ammonium chloride solution was investigated. The effects of stirring speed （150？400 r/min）, leaching temperature （95-108 ℃, particle size of zinc silicate （61-150 μm） and the concentration of ammonium chloride （3.5-5.5 mol/L） on leaching rate of zinc were studied. The results show that decreasing the particle size of zinc silicate and increasing the leaching temperature and concentration of ammonium chloride can obviously enhance the leaching rate of zinc. Among the kinetic models of the porous solids tested, the grain model with porous diffusion control can well describe the zinc leaching kinetics. The apparent activation energy of the leaching reaction is 161.26 kJ/mol and the reaction order with respect to ammonium chloride is 3.5.展开更多
The adsorption isotherm of sodium polyacrylate on dicalcium silicate（2CaO-SiO2） in sodium aluminate solution at 80 ℃ was studied.The type of surface adsorption of sodium polyacrylate is saturated adsorption,and the...The adsorption isotherm of sodium polyacrylate on dicalcium silicate（2CaO-SiO2） in sodium aluminate solution at 80 ℃ was studied.The type of surface adsorption of sodium polyacrylate is saturated adsorption,and the adsorption behavior belongs to L-type,according with the monolayer adsorption model of Langmuir equation.The surface coverage of sodium polyacrylate is 1.06 mol/μm2.The relation curve between the surface pressure and the molecular area of adsorption film was obtained by Gibbs formula.The variation of interfacial energy caused by adsorption as well as the relationship between the relation curve and the type of adsorption was discussed.展开更多
Silicate sol post-treatment was applied to form a complete composite coating on the phosphated zinc layer. The chemical compositions of the coatings were investigated using XPS. The coated samples were firstly scratch...Silicate sol post-treatment was applied to form a complete composite coating on the phosphated zinc layer. The chemical compositions of the coatings were investigated using XPS. The coated samples were firstly scratched and then exposed to the neutral salt spray(NSS) chamber for different time. The microstructure and chemical compositions of the scratches were studied using SEM and EDS. And the non-scratched coated samples were compared. The self-healing mechanism of the composite coatings was discussed. The results show that during corrosion, the self-healing ions in composite coatings dissolve, diffuse and transfer to the scratches or the defects, and then recombine with Zn2+ to form insoluble compound, which deposits and covers the exposed zinc. The corrosion products on the scratches contain silicon, phosphorous, oxygen, chloride and zinc, and they are compact, fine, needle and flake, effectively inhibiting the corrosion formation and expansion of the exposed zinc layer. The composite coatings have good self-healing ability.展开更多
The influences of sodium silicate on manganese electrodeposition in sulfate solution were investigated. Manganese electrodeposition experiments indicate that a certain amount of sodium silicate can improve cathode cur...The influences of sodium silicate on manganese electrodeposition in sulfate solution were investigated. Manganese electrodeposition experiments indicate that a certain amount of sodium silicate can improve cathode current efficiency and initial pH 7.0?8.0 is the optimized pH for high cathode current efficiency. The analyses of scanning electron microscopy (SEM) and X-ray diffraction (XRD) indicate the compact morphology and nanocrystalline structure of electrodeposits. X-ray photoelectron spectrometry (XPS) analysis shows that the elements of Mn, Si and O exist in the deposit. The solution chemistry calculations of sulfate electrolyte and sodium silicate solution indicate that species of Mn2+, MnSO4, Mn(SO4)2?2 , Mn2+, MnSiO3, Mn(NH3)2+, SiO32?and HSiO3? are the main active species during the process of manganese electrodeposition. The reaction trend between Mn2+ and Si-containing ions is confirmed by the thermodynamic analysis. In addition, polarization curve tests confirm that sodium silicate can increase the overpotential of hydrogen evolution reaction, and then indirectly improve the cathode current efficiency.展开更多
The distributions of local structural units of calcium silicate melts were quantified by means of classical molecular dynamics simulation and a newly constructed structural thermodynamic model. The distribution of fiv...The distributions of local structural units of calcium silicate melts were quantified by means of classical molecular dynamics simulation and a newly constructed structural thermodynamic model. The distribution of five kinds of Si-O tetrahedra Qi from these two methods was compared with each other and also with the experimental Raman spectra, an excellent agreement was achieved. These not only displayed the panorama distribution of microstructural units in the whole composition range, but also proved that the thermodynamic model is suitable for the utilization as the subsequent application model of spectral experiments for the thermodynamic calculation. Meanwhile, the five refined regions mastered by different disproportionating reactions were obtained. Finally, the distributions of two kinds of connections between Qi were obtained, denoted as Qi-Ca-Qj and Qi-[Ob]-Qj, from the thermodynamic model, and a theoretical verification was given that the dominant connections for any composition are equivalent connections.展开更多
Airborne silicate pollutants in flight corridors pose a serious threat to aviation safety whose severity is directly linked to the wettability of molten silicates on thermal barrier coatings(TBCs)at high temperatures(...Airborne silicate pollutants in flight corridors pose a serious threat to aviation safety whose severity is directly linked to the wettability of molten silicates on thermal barrier coatings(TBCs)at high temperatures(1200–2000℃).Despite its importance,the wettability of silicate melt on TBCs has not been well investigated.In particular,the surface morphology characteristics of TBCs can be expected to have a first-order effect on the wettability of silicate melt on such TBCs.Here,a series of atmospheric plasma spray(APS)yttria-stabilized zirconia(YSZ)TBCs with varying surface roughness were generated through the application of mechanical polishing.The metastable nonwetting behavior of three representative types of airborne silicate ash(volcanic ash,fly ash and a synthetic calcium–magnesium–aluminum–silicates(CMAS)powder)on these TBCs with varying surface roughness was investigated.It was observed that the smoother the surface of TBCs was,the larger the contact angle was with the molten silicate melts,and consequently,the smaller the area of damage was on the TBCs.Thus,the reduction in TBCs surface roughness(here via mechanical polishing)led to an improvement in the wetting and spreading resistance of TBCs to silicate melts at high temperature.In support of these observations and conclusions,the surface morphology of the TBC(both before and after polishing)had been characterized,and the mechanism of the surface roughness-dependence of wettability had been discussed.These results should contribute to reducing the deposition rate of silicate melt on TBCs,thus extending the lifetime of turbine blades and reducing maintenance costs.展开更多
The Sarcheshmeh copper flotation circuit is producing 5× 10^4 t copper concentrate per month with an averaging grade of 28% Cu in rougher, cleaner and recleaner stages. In recent years, with the increase in the o...The Sarcheshmeh copper flotation circuit is producing 5× 10^4 t copper concentrate per month with an averaging grade of 28% Cu in rougher, cleaner and recleaner stages. In recent years, with the increase in the open pit depth, the content of aluminosilicate minerals increased in plant feed and subsequently in flotation concentrate. It can motivate some problems, such as unwanted consumption of reagents, decreasing of the copper concentrate grade, increasing of Al2O3 and SiO2 in the copper concentrate, and needing a higher temperature in the smelting process. The evaluation of the composite samples related to the most critical working period of the plant shows that quartz, illite, biotite, chlorite, orthoclase, albeit, muscovite, and kaolinite are the major Al2O3 and SiO2 beating minerals that accompany chalcopyrite, chalcocite, and covellite minerals in the plant feed. The severe alteration to clay minerals was a general rule in all thin sections that were prepared from the plant feed. Sieve analysis of the flotation concentrate shows that Al2O3 and SiO2 bearing minerals in the flotation concentrate can be decreased by promoting the size reduction from 53 to 38 μm. Interlocking of the Al2O3 and SiO2 bearing minerals with chalcopyrite and chalcocite is the occurrence mechanism of silicate and aluminosilicate minerals in the flotation concentrate. The dispersed form of interlocking is predominant.展开更多
Slime-forming bacteria were isolated from soils, rock surface and earthworm intestine, and their effects on dissolving silicate minerals and tomato growth were examined. One of the bacteria, Bacillus mucilaginosus RGB...Slime-forming bacteria were isolated from soils, rock surface and earthworm intestine, and their effects on dissolving silicate minerals and tomato growth were examined. One of the bacteria, Bacillus mucilaginosus RGBc13, had particularly strong ability to form slime and dissolve silicates. RGBc13 could also colonize and develop in both non-rhizosphere and rhizosphere soil. Total number of slime-forming bacteria increased from 2.9 × 103 cfu·g-1and 8.4 × 103 cfu·g-1 to 9.6 × 106 cfu·g-1 and 6.0 × 107 cfu·g-1 in the non-rhizosphere and rhizosphere soils respectively. Potassium and phosphorus nutritional conditions in the rhizosphere were markedly improved through inoculation of this bacterium. Available K and P respectively increased from 25. 86 and 3. 63mg · kg-1 in the non-rhizosphere soil to 91. 23 and 5. 74mg · kg-1 in the rhizosphere soil. Tomato biomass increased by 125%, K and P uptakes were more than 150%, greater than the non-inoculation. Thus, there is a potential in applying RGBcl3 for improving plant K and P nutrition.展开更多
To clarify the precipitation of silica hydrate from the real desilication solutions of aluminosilicate solid wastes by adding seeds and improve integrated waste utilization,the seeded precipitation was studied using s...To clarify the precipitation of silica hydrate from the real desilication solutions of aluminosilicate solid wastes by adding seeds and improve integrated waste utilization,the seeded precipitation was studied using synthesized sodium silicate solution containing different inorganic salt impurities.The results show that sodium chloride,sodium sulfate,sodium carbonate,or calcium chloride can change the siloxy group structure.The number of high-polymeric siloxy groups decreases with increasing sodium chloride or sodium sulfate concentration,which is detrimental to seeded precipitation.Calcium chloride favors the polymerization of silicate ions,and even the chain groups precipitate with the precipitation of high-polymeric sheet and cage-like siloxy groups.The introduced sodium cations in sodium carbonate render a more open network structure of high-polymeric siloxy groups,although the carbonate ions favor the polymerization of siloxy groups.No matter how the four impurities affect the siloxy group structure,the precipitates are always amorphous opal-A silica hydrate.展开更多
The effects of matrix silicate and experimental conditions on the determination of iron in flame atomic absorption spectrometry （FAAS） were investigated. It was found that boric acid as a matrix modifier obviously e...The effects of matrix silicate and experimental conditions on the determination of iron in flame atomic absorption spectrometry （FAAS） were investigated. It was found that boric acid as a matrix modifier obviously eliminated silicate interference. Under the optimum operating conditions, the determination results of iron in layered crystal sodium disilicate and sodium silicate samples by FAAS were satisfactory. The linear range of calibration curve is 0-10.5 μg.mL^-1, the relative standard deviation of method is 1.2%-2.2%, the recovery of added iron is 96.0%- 101%, the sensitivity is 0.19 μg.mL^-l and the detection limit is 77 ng.mL^-1. The effect of the determination of iron of the standard curve method, standard addition calibration and colorimetry method was the same, but the first has the merits of rapid sample preparation, reduced contamination risks and fast analysis.展开更多
This study aims to investigate the behavior of alkali activated mortar,which is made of naturally available magnesium silicate as source material.For magnesium silicate,ultrafine natural steatite powder(UFNSP)is used ...This study aims to investigate the behavior of alkali activated mortar,which is made of naturally available magnesium silicate as source material.For magnesium silicate,ultrafine natural steatite powder(UFNSP)is used as the primary source of binder,and the activation is initiated through the alkali liquid which is proportioned in various combinations of silicate to hydroxide ratio(Na_(2)SiO_(3)/Na OH)ratio,and this ratio in this study varies from 1 to 3.The UFNSP is calcined at two difierent temperatures,700 and 1000℃.The mortar mix is proportioned as 1:3 between powder and the fine aggregate,and the mortar is prepared with hydroxide molarity(M)of 10 M.The mortar is cured for 48 hours at 60℃and the compressive strength was studied.All the mix were studied for its microstructural behavior along with compressive strength.The mix proportion of the mortar,and the results obtained through microstructural characterization were combinedly formed as input for artificial neural network(ANN)predictive modelling.The model is designed to predict the compressive strength,which is trained through Bayesian regularization algorithm with varying hidden neurons of 7 to 10.This experimental and predictive study shows that the strength is influenced by both Na_(2)SiO_(3)/Na OH ratio and calcination process.And the ANN is influenced by mainly calcination temperature and uncorrelation occurs in selected samples of 1000℃calcined UFNSP mix.展开更多
基金support from the National Natural Science Foundation of China(grant number 52075544)Innovation Funds of Jihua Laboratory(X220971UZ230)+1 种基金Basic and Applied Basic Research Foundation of Guangdong Province(2022A1515110649)Funds from Research Platforms of Guangdong Higher Education Institutes(2022ZDJS038).
文摘Efficient lubrication of magnesium alloys is a highly challenging topic in the field of tribology.In this study,magnesium silicate hydroxide(MSH)nanotubes with serpentine structures were synthesized.The tribological behavior of AZ91D magnesium alloy rubbed against GCr15 steel was studied under lubricating oil with surface-modified MSH nanotubes as additives.The effects of the concentration,applied load,and reciprocating frequency on the friction and wear of the AZ91D alloy were studied using an SRV-4 sliding wear tester.Results show a decrease of 18.7–68.5%in friction coefficient,and a reduction of 19.4–54.3%in wear volume of magnesium alloy can be achieved by applying the synthetic serpentine additive under different conditions.A suspension containing 0.3 wt.%MSH was most efficient in reducing wear and friction.High frequency and medium load were more conducive to improving the tribological properties of magnesium alloys.A series of beneficial physical and chemical processes occurring at the AZ91D alloy/steel interface can be used to explain friction and wear reduction based on the characterization of the morphology,chemical composition,chemical state,microstructure,and nanomechanical properties of the worn surface.The synthetic MSH,with serpentine structure and nanotube morphology,possesses excellent adsorbability,high chemical activity,and good self-lubrication and catalytic activity.Therefore,physical polishing,tribochemical reactions,and physicalchemical depositions can occur easily on the sliding contacts.A dense tribolayer with a complex composition and composite structure was formed on the worn surface.Its high hardness,good toughness and plasticity,and prominent lubricity resulted in the improvement of friction and wear,making the synthetic MSH a promising efficient oil additive for magnesium alloys under boundary and mixed lubrication.
基金Funded by the Natural Science Foundation of Jiangsu Province(No.BK20241529)China Postdoctoral Science Foundation(No.2024M750736)。
文摘This study aims to develop a chloride diffusion simulation method that considers the hydration microstructure and pore solution properties during the hydration of tricalcium silicate(C3S).The method combines the hydration simulation,thermodynamic calculation,and finite element analysis to examine the effects of pore solution,including effect of electrochemical potential,effect of chemical activity,and effect of mechanical interactions between ions,on the chloride effective diffusion coefficient of hydrated C3S paste.The results indicate that the effect of electrochemical potential on chloride diffusion becomes stronger with increasing hydration age due to the increase in the content of hydrated calcium silicate;as the hydration age increases,the effect of chemical activity on chloride diffusion weakens when the number of diffusible elements decreases;the effect of mechanical interactions between ions on chloride diffusion decreases with the increase of hydration age.
文摘Sm^(3+)-doped materials exhibit red and orange emissions in the visible light region,showing broad applica⁃tion prospects in both laser and display material fields.However,the inherent small emission and absorption cross-sections of Sm^(3+)result in low luminous efficiency,posing challenges for achieving high-quality solid-state lighting.Here,the excellent white emission of Sm^(3+)doped lithium aluminum silicate(LAS)glass was realized by introducing the Ag aggregates through Ag ion exchange.Under 395 nm excitation,the Ag-doped samples exhibit significant fluo⁃rescence enhancement with color coordinates close to the equal energy white point E(0.33,0.33)and a color ren⁃dering index(CRI)of 81.8.The study reveals that the surface plasmon resonance(SPR)effect of Ag nanoparticles enhances the luminescence of Sm^(3+),while the energy transfer mechanism between Ag^(+)and Sm^(3+)also promotes fluores⁃cence enhancement.By adjusting the concentration of AgNO_(3) and the exchange time,a series of high-quality full-spectrum white light emissions were obtained,indicating that the Ag ion-exchanged Sm^(3+)-doped LAS glass has good application potential in the development of solid-state lighting devices.Moreover,variations in the excitation wave⁃length can effectively tune the emission color,further demonstrating the tunability and practicality of this material in optoelectronic applications.
基金Project supported by the National Natural Science Foundation of China (52064002)Guangxi Science and Technology Major Project(AA23073018)。
文摘A novel method for scandium recovery is proposed through high-surface area silanol-rich silica sorbents which were prepared with calcium silicate hydrate(C-S-H) as raw material.Two types of silanol-rich silica particles,i.e.,LAC-S(silica derived from acid leaching of amorphous C-S-H) and LLC-S(silica derived from acid leaching of low-crystallinity C-S-H) are obtained after calcium ions are removed from both amorphous and low-crystallinity forms of C-S-H through a facile acid leaching process(3 mol/L,25℃,24 h).(29)^Si NMR spectroscopy reveals that the proportion of silicon atoms carrying silanol groups increases from less than 43% to over 80% when silica particles are transferred from a dry state to an aqueous solution.Batch adsorption experiments were conducted to evaluate the sorption performance and selectivity of these silica sorbents toward Sc(Ⅲ).The scandium sorption capacities of LAC-S and LLC-S at an equilibrium pH of 4.2 are 174.45 and 129.57 mg/g,respectively.The separation factors(SFSc/Ln) of both silica particles exceed 1000 in the initial pH range of 3.5-5.The loaded scandium ions are recovered with 3 mol/L hydrochloric acid and the sorbents exhibit good reusability.This strategy provides an efficient and green method for recovering scandium from aqueous solutions.
基金supported by the Young Elite Scientists Sponsorship Program by CAST(No.2023QNRC001)Natural Science Foundation of Hunan Province,China(No.2024JJ2074)supported in part by the High Performance Computing Center of Central South University,China and the Pawsey Supercomputing Centre with funding from the Australian Government and the Government of Western Australia.
文摘An in-depth understanding of the hydration mechanism of tricalcium silicate is an important basis for optimizing cement strength development.In this study,the adsorption of water molecules onto the M3-C3S(001)surface at different water coverage levels(θ=1/5,2/5,3/5,4/5,and 1)was investigated using first-principles calculations.The results demonstrate that the conclusions obtained for single water molecule adsorption cannot be fully applied to multiple water molecule adsorption.The total adsorption energies become more negative with increasing water coverage,while the average adsorption energy of each water molecule becomes more positive with increasing water coverage.The water–water interactions reduce the water–surface interactions and are responsible for the anticooperative adsorption of multiple water molecules onto M3-C_(3)S(001).The formation of Ca–OH(–Ca)bonds favors the detachment of Ca from co-valent oxygen,which reveals the significant role of dissociative adsorption.This work aims to extend the water adsorption study on M3-C3S(001)from single water molecule adsorption to multiple water molecule adsorption,providing more detailed insights into the initial water reaction on the C3S surface.
基金the Doctoral Research Startup Fund of Hubei University of Science and Technology(Grant No.BK202504)the Natural Science Foundation of Liaoning Province(Grant No.2023-MS-115).
文摘Aqueous zinc-based energy storage systems offer high theoretical specific capacity,low cost,intrinsic safety,and environmental compatibility,positioning them as promising candidates for next-generation energy storage and conversion technologies.However,issues such as zinc dendrite growth,hydrogen evolution reaction(HER),and surface passivation hinder their practical deployment.To address these challenges,a hollow nanotubular magnesium silicate(denoted MgSi)interfacial layer was constructed on the zinc metal anode(Zn@MgSi).The unique layer structure and negatively charged surface of MgSi facilitate the desolvation of[Zn(H_(2)O)_(6)]^(2+)by stripping water molecules,while temporarily immobilizing Zn^(2+)to suppress random diffusion.The combined effects of the electric field-guided Zn^(2+)distribution and rapid ion transport through the layer structure co-regulate Zn^(2+)flux,leading to uniform,dendrite-free zinc deposition.Consequently,the Zn@MgSi symmetric cell demonstrates a high Zn^(2+)transference number(0.64),extended cycling life exceeding 1600 h at 1 mA cm^(−2),and stable operation for 200 h at 5 mA cm^(−2).Furthermore,zinc-ion hybrid capacitors employing Zn@MgSi electrodes exhibit excellent cycling stability over 5000 cycles.This work highlights the efficacy of artificial interfacial layers in stabilizing zinc metal anodes and provides valuable insights into the development of advanced aqueous zinc-ion energy storage systems.
基金supported by the National Natural Science Foundation of China(Grant Nos.42030710 and 52308345)the National Key Research and Development Program of China(Grant No.2023YFC3707903).
文摘Heavy metal-contaminated sites are primarily treated via solidification and adsorption.Calcium silicate hydrate(C-S-H)is generated during the soil stabilization process and contributes significantly to the strength and durability of the stabilized soil.To understand how the soil moisture content and heavy metal concentration affect the transport of heavy metals and the tensile strength of C-S-H,this study performed molecular dynamics(MD)simulations under different moisture and concentration levels.The results showed that Pb2+presented the highest adsorption to the surface of C-S-H due to its strong electrostatic interaction energy.The adsorption density peaks of Pb2+were 1.5–5 times greater than those of Cd2+and Zn2+.Zn2+and Cd2+ions were more likely to be adsorbed onto water molecules and form a larger hydrated radius than Pb2+.The adsorption of heavy metals onto C-S-H initially increased as the metal concentration increased and then decreased because of the limited sorption sites on C-S-H.The diffusion coefficients of the multicomponent metals in C-S-H showed no consistent trends.The maximum tensile strength of C-S-H decreased with increasing soil moisture and heavy metal concentrations.The tensile stress increased approximately linearly with strain until it reached a peak,after which it gradually declined but remained above zero,indicating good ductility and toughness under unsaturated conditions.These findings offer valuable molecular insights into the interactions between C-S-H and heavy metals and soil moisture,thereby advancing our understanding of their combined effects on soil stabilization.
基金Project supported by the Natural Science Foundation of The Educational Department of Liaoning Province(JYTMS20231627)。
文摘The emission wavelength of current near-infrared phosphors activated by Cr^(3+)is generally smaller than 900 nm in near-infrared(NIR)Ⅰ region,and it is extremely challenging and is of great practical significance to realize emission towards NIR-Ⅱ region.In this study,a novel Cr^(3+)excited KSrScSi_(2)O_(7)silicate broad-band phosphor was prepared using the traditional solid-state method.Cr^(3+)resides in a weak crystal field in the KSrScSi_(2)O_(7)lattice and exhibits broad-band near-infrared emission at 984 nm,longer than those of most Cr^(3+)activated phosphors,under 493 nm blue light excitation.This is due to the stro ng charge polarization caused by the unique local coordination environment of the silicate matrix,which leads to a reduction in the crystal field splitting energy of the[ScO_(6)]octahedron where Cr^(3+)is located and the downward shift of the^(4)T_(2)energy level.The optimal doping concentration of Cr^(3+)is found to be 2 mol%,and the quenching mechanism is dipole-dipole interaction.Compared to the phosphors with similar emission wavelengths(λ_(em)>900 nm),KSrScSi_(2)O_(7):Cr^(3+)demonstrates outstanding advantages in various aspects of luminescent performance.The fabricated phosphor-converted light-emitting diode(pc-LED)is shown to have the potential for night vision and non-invasive imaging.Novel application of KSrScSi_(2)O_(7):xCr^(3+)as stable green ceramic pigments is also explored.The KSrScSi_(2)O_(7):xCr^(3+)powders show a bright yellowish green appearance,and the KSrScSi_(2)O_(7):0.02Cr^(3+)typical composition has chromaticity values of L^(*)=82.73,a^(*)=-8.53,b^(*)=7.97.Remarkably,the glazing samples using KSrScSi_(2)O_(7):xCr^(3+)as pigments well retain the bright color after 1200℃sintering in different atmospheres.Therefore,multifunctional applications of KSrScSi_(2)O_(7):xCr^(3+)for near-infrared spectroscopy and as ceramic pigments are achieved in this work.
文摘The paper overviews the research and application of silicate plugging agent, according to the different mechanisms and application forms, the plugging agent is divided into silicate gel, silicate precipitation, silicate/polymer, silicate/surfactant, silicate gel/foam and so on. This paper chiefly introduces the conception, mechanism and development tendency of the different systems mentioned above. The development tendency manifests as fully utilize personal properties and cooperate with other plugging agents or technologies, including the study of reaction mechanism, combination of plugging agent, grasping water flood timing, developing deep profile control and water shutoff technology, combining with other measures (chemicals huff and puff), in order to play the role of such blocking agents, further enhance oil recovery.
基金Project(2014CB643404)supported by the National Basic Research Program of ChinaProject(51374254)supported by the National Natural Science Foundation of China
文摘The leaching kinetics of zinc silicate in ammonium chloride solution was investigated. The effects of stirring speed （150？400 r/min）, leaching temperature （95-108 ℃, particle size of zinc silicate （61-150 μm） and the concentration of ammonium chloride （3.5-5.5 mol/L） on leaching rate of zinc were studied. The results show that decreasing the particle size of zinc silicate and increasing the leaching temperature and concentration of ammonium chloride can obviously enhance the leaching rate of zinc. Among the kinetic models of the porous solids tested, the grain model with porous diffusion control can well describe the zinc leaching kinetics. The apparent activation energy of the leaching reaction is 161.26 kJ/mol and the reaction order with respect to ammonium chloride is 3.5.
基金Project(50974036)supported by the National Natural Science Foundation of China
文摘The adsorption isotherm of sodium polyacrylate on dicalcium silicate（2CaO-SiO2） in sodium aluminate solution at 80 ℃ was studied.The type of surface adsorption of sodium polyacrylate is saturated adsorption,and the adsorption behavior belongs to L-type,according with the monolayer adsorption model of Langmuir equation.The surface coverage of sodium polyacrylate is 1.06 mol/μm2.The relation curve between the surface pressure and the molecular area of adsorption film was obtained by Gibbs formula.The variation of interfacial energy caused by adsorption as well as the relationship between the relation curve and the type of adsorption was discussed.
基金Project(2012J05099)supported by the Natural Science Foundation of Fujian Province,ChinaProject(YKJ10021R)supported by the Scientific Research Project of Xiamen University of Technology
文摘Silicate sol post-treatment was applied to form a complete composite coating on the phosphated zinc layer. The chemical compositions of the coatings were investigated using XPS. The coated samples were firstly scratched and then exposed to the neutral salt spray(NSS) chamber for different time. The microstructure and chemical compositions of the scratches were studied using SEM and EDS. And the non-scratched coated samples were compared. The self-healing mechanism of the composite coatings was discussed. The results show that during corrosion, the self-healing ions in composite coatings dissolve, diffuse and transfer to the scratches or the defects, and then recombine with Zn2+ to form insoluble compound, which deposits and covers the exposed zinc. The corrosion products on the scratches contain silicon, phosphorous, oxygen, chloride and zinc, and they are compact, fine, needle and flake, effectively inhibiting the corrosion formation and expansion of the exposed zinc layer. The composite coatings have good self-healing ability.
基金Project(2015BAB17B01)supported by the National Science and Technology Support Program of ChinaProject(21376273)supported by the National Natural Science Foundation of China
文摘The influences of sodium silicate on manganese electrodeposition in sulfate solution were investigated. Manganese electrodeposition experiments indicate that a certain amount of sodium silicate can improve cathode current efficiency and initial pH 7.0?8.0 is the optimized pH for high cathode current efficiency. The analyses of scanning electron microscopy (SEM) and X-ray diffraction (XRD) indicate the compact morphology and nanocrystalline structure of electrodeposits. X-ray photoelectron spectrometry (XPS) analysis shows that the elements of Mn, Si and O exist in the deposit. The solution chemistry calculations of sulfate electrolyte and sodium silicate solution indicate that species of Mn2+, MnSO4, Mn(SO4)2?2 , Mn2+, MnSiO3, Mn(NH3)2+, SiO32?and HSiO3? are the main active species during the process of manganese electrodeposition. The reaction trend between Mn2+ and Si-containing ions is confirmed by the thermodynamic analysis. In addition, polarization curve tests confirm that sodium silicate can increase the overpotential of hydrogen evolution reaction, and then indirectly improve the cathode current efficiency.
基金Project(2012CB722805)supported by the National Basic Research Program of ChinaProjects(50504010,50974083,51174131,51374141)supported by the National Natural Science Foundation of China+1 种基金Project(50774112)supported by the Joint Fund of NSFC and Baosteel,ChinaProject(07QA4021)supported by the Shanghai"Phosphor"Science Foundation,China
文摘The distributions of local structural units of calcium silicate melts were quantified by means of classical molecular dynamics simulation and a newly constructed structural thermodynamic model. The distribution of five kinds of Si-O tetrahedra Qi from these two methods was compared with each other and also with the experimental Raman spectra, an excellent agreement was achieved. These not only displayed the panorama distribution of microstructural units in the whole composition range, but also proved that the thermodynamic model is suitable for the utilization as the subsequent application model of spectral experiments for the thermodynamic calculation. Meanwhile, the five refined regions mastered by different disproportionating reactions were obtained. Finally, the distributions of two kinds of connections between Qi were obtained, denoted as Qi-Ca-Qj and Qi-[Ob]-Qj, from the thermodynamic model, and a theoretical verification was given that the dominant connections for any composition are equivalent connections.
基金This study was financially supported by the National Science and Technology Major Project(No.2017-VI-0010-0081)the Program of the Ministry of Education of China for Introducing Talents of Discipline to Universities(No.B17002)+2 种基金the National Natural Science Foundation of China(No.51901011)the“Freigeist”Fellowship of the Volkswagenstiftung on“Volcanic Ash Deposition in Jet Engines”(VADJEs,No.89705)China Scholarship Council(CSC).
文摘Airborne silicate pollutants in flight corridors pose a serious threat to aviation safety whose severity is directly linked to the wettability of molten silicates on thermal barrier coatings(TBCs)at high temperatures(1200–2000℃).Despite its importance,the wettability of silicate melt on TBCs has not been well investigated.In particular,the surface morphology characteristics of TBCs can be expected to have a first-order effect on the wettability of silicate melt on such TBCs.Here,a series of atmospheric plasma spray(APS)yttria-stabilized zirconia(YSZ)TBCs with varying surface roughness were generated through the application of mechanical polishing.The metastable nonwetting behavior of three representative types of airborne silicate ash(volcanic ash,fly ash and a synthetic calcium–magnesium–aluminum–silicates(CMAS)powder)on these TBCs with varying surface roughness was investigated.It was observed that the smoother the surface of TBCs was,the larger the contact angle was with the molten silicate melts,and consequently,the smaller the area of damage was on the TBCs.Thus,the reduction in TBCs surface roughness(here via mechanical polishing)led to an improvement in the wetting and spreading resistance of TBCs to silicate melts at high temperature.In support of these observations and conclusions,the surface morphology of the TBC(both before and after polishing)had been characterized,and the mechanism of the surface roughness-dependence of wettability had been discussed.These results should contribute to reducing the deposition rate of silicate melt on TBCs,thus extending the lifetime of turbine blades and reducing maintenance costs.
文摘The Sarcheshmeh copper flotation circuit is producing 5× 10^4 t copper concentrate per month with an averaging grade of 28% Cu in rougher, cleaner and recleaner stages. In recent years, with the increase in the open pit depth, the content of aluminosilicate minerals increased in plant feed and subsequently in flotation concentrate. It can motivate some problems, such as unwanted consumption of reagents, decreasing of the copper concentrate grade, increasing of Al2O3 and SiO2 in the copper concentrate, and needing a higher temperature in the smelting process. The evaluation of the composite samples related to the most critical working period of the plant shows that quartz, illite, biotite, chlorite, orthoclase, albeit, muscovite, and kaolinite are the major Al2O3 and SiO2 beating minerals that accompany chalcopyrite, chalcocite, and covellite minerals in the plant feed. The severe alteration to clay minerals was a general rule in all thin sections that were prepared from the plant feed. Sieve analysis of the flotation concentrate shows that Al2O3 and SiO2 bearing minerals in the flotation concentrate can be decreased by promoting the size reduction from 53 to 38 μm. Interlocking of the Al2O3 and SiO2 bearing minerals with chalcopyrite and chalcocite is the occurrence mechanism of silicate and aluminosilicate minerals in the flotation concentrate. The dispersed form of interlocking is predominant.
文摘Slime-forming bacteria were isolated from soils, rock surface and earthworm intestine, and their effects on dissolving silicate minerals and tomato growth were examined. One of the bacteria, Bacillus mucilaginosus RGBc13, had particularly strong ability to form slime and dissolve silicates. RGBc13 could also colonize and develop in both non-rhizosphere and rhizosphere soil. Total number of slime-forming bacteria increased from 2.9 × 103 cfu·g-1and 8.4 × 103 cfu·g-1 to 9.6 × 106 cfu·g-1 and 6.0 × 107 cfu·g-1 in the non-rhizosphere and rhizosphere soils respectively. Potassium and phosphorus nutritional conditions in the rhizosphere were markedly improved through inoculation of this bacterium. Available K and P respectively increased from 25. 86 and 3. 63mg · kg-1 in the non-rhizosphere soil to 91. 23 and 5. 74mg · kg-1 in the rhizosphere soil. Tomato biomass increased by 125%, K and P uptakes were more than 150%, greater than the non-inoculation. Thus, there is a potential in applying RGBcl3 for improving plant K and P nutrition.
基金financial support from the National Natural Science Foundation of China(No.52074364)。
文摘To clarify the precipitation of silica hydrate from the real desilication solutions of aluminosilicate solid wastes by adding seeds and improve integrated waste utilization,the seeded precipitation was studied using synthesized sodium silicate solution containing different inorganic salt impurities.The results show that sodium chloride,sodium sulfate,sodium carbonate,or calcium chloride can change the siloxy group structure.The number of high-polymeric siloxy groups decreases with increasing sodium chloride or sodium sulfate concentration,which is detrimental to seeded precipitation.Calcium chloride favors the polymerization of silicate ions,and even the chain groups precipitate with the precipitation of high-polymeric sheet and cage-like siloxy groups.The introduced sodium cations in sodium carbonate render a more open network structure of high-polymeric siloxy groups,although the carbonate ions favor the polymerization of siloxy groups.No matter how the four impurities affect the siloxy group structure,the precipitates are always amorphous opal-A silica hydrate.
文摘The effects of matrix silicate and experimental conditions on the determination of iron in flame atomic absorption spectrometry （FAAS） were investigated. It was found that boric acid as a matrix modifier obviously eliminated silicate interference. Under the optimum operating conditions, the determination results of iron in layered crystal sodium disilicate and sodium silicate samples by FAAS were satisfactory. The linear range of calibration curve is 0-10.5 μg.mL^-1, the relative standard deviation of method is 1.2%-2.2%, the recovery of added iron is 96.0%- 101%, the sensitivity is 0.19 μg.mL^-l and the detection limit is 77 ng.mL^-1. The effect of the determination of iron of the standard curve method, standard addition calibration and colorimetry method was the same, but the first has the merits of rapid sample preparation, reduced contamination risks and fast analysis.
文摘This study aims to investigate the behavior of alkali activated mortar,which is made of naturally available magnesium silicate as source material.For magnesium silicate,ultrafine natural steatite powder(UFNSP)is used as the primary source of binder,and the activation is initiated through the alkali liquid which is proportioned in various combinations of silicate to hydroxide ratio(Na_(2)SiO_(3)/Na OH)ratio,and this ratio in this study varies from 1 to 3.The UFNSP is calcined at two difierent temperatures,700 and 1000℃.The mortar mix is proportioned as 1:3 between powder and the fine aggregate,and the mortar is prepared with hydroxide molarity(M)of 10 M.The mortar is cured for 48 hours at 60℃and the compressive strength was studied.All the mix were studied for its microstructural behavior along with compressive strength.The mix proportion of the mortar,and the results obtained through microstructural characterization were combinedly formed as input for artificial neural network(ANN)predictive modelling.The model is designed to predict the compressive strength,which is trained through Bayesian regularization algorithm with varying hidden neurons of 7 to 10.This experimental and predictive study shows that the strength is influenced by both Na_(2)SiO_(3)/Na OH ratio and calcination process.And the ANN is influenced by mainly calcination temperature and uncorrelation occurs in selected samples of 1000℃calcined UFNSP mix.
