The increasing demand for sustainable energy storage solutions has intensified the focus on high-performance supercapaci-tors,known for their rapid charge/discharge capabilities,high power density,and long cycle life....The increasing demand for sustainable energy storage solutions has intensified the focus on high-performance supercapaci-tors,known for their rapid charge/discharge capabilities,high power density,and long cycle life.Polyurethane(PU)-based materials have gained attention as promising candidates for supercapacitor electrodes,due to their flexibility,mechanical robustness,and tunable properties.It is important to clarify that PU typically does not contribute directly to charge storage via adsorption or pseudocapacitive mechanisms.Instead,PU serves as a flexible scaffold,a binder,or a precursor for the preparation of heteroatom-doped carbon materials upon thermal treatment.Thus,the term'PU-based'in this review refers to PU-supported or PU-derived composites,where PU enables structural or functional integration of active electrode Materi-als.Polyurethane composites incorporating graphene oxide have demonstrated a specific capacitance of 758.8 mF/cm^(2)with capacitance retention of 92%over 5,000 cycles.Other PU-based electrodes have achieved energy densities up to 22.5 Wh/kg and power densities of 1472.7 W/kg,reflecting their potential for high-performance energy storage applications.Despite these advantages,challenges,such as low intrinsic conductivity and the environmental impact of traditional synthesis methods,limit their widespread adoption.Conventional PU composites often incorporate conductive additives like carbon materi-als,metal oxides,or conductive polymers to enhance their electrochemical performance,yet these approaches may involve non-renewable or toxic components.Developing green energy materials that adhere to sustainability and green chemistry principles is crucial to address these limitations.This includes using renewable resources,environmentally friendly process-ing techniques,and recyclable materials to reduce the ecological footprint and meet the growing need for sustainable energy storage technologies.This review highlights current trends in developing eco-friendly supercapacitor materials,addressing key challenges such as limited conductivity and complex processing.It uniquely integrates green chemistry principles with advances in polyurethane composites,emphasizing sustainable feedstocks,heteroatom doping,and functional nanomateri-als.By combining these aspects,this review provides a comprehensive perspective not fully covered in existing literature.展开更多
Annual haze in Northern Thailand has become increasingly severe,impacting health and the environment.How-ever,the sources of the haze remain poorly quantified due to limited observational data on aerosol molecular tra...Annual haze in Northern Thailand has become increasingly severe,impacting health and the environment.How-ever,the sources of the haze remain poorly quantified due to limited observational data on aerosol molecular tracers.This study comprehensively investigates chemical composition of PM_(2.5),including both inorganic and organic compounds throughout haze and post-haze periods in 2019 at a rural site of Northern Thailand.Average PM_(2.5) concentrations during haze and post-haze period were 87±36 and 21±11μg/m^(3),respectively.Organic matter was the dominant contributor in PM_(2.5) mass,followed by water soluble inorganic ions and mineral dust.Molecular markers,including levoglucosan,dehydroabietic acid,and 4-nitrocatechol,and ions(Cl^(-),and K^(+)),were used to characterize low haze(PM_(2.5)<100μg/m^(3))and episodic haze(PM_(2.5)>100μg/m^(3)).Low haze is associated with local aerosols from agricultural waste burning,while episodic haze is linked to aged aerosols from mixed agricultural waste,softwood,and hardwood burning.Source apportionment incorporating these molecular markers in receptor modelling(Positive matrix factorization),identified three distinct biomass burning sources:mixed,local,and aged biomass burnings,contributing 31,19 and 13%of PM_(2.5) during haze period.During post-haze period,contributions shifted,with local biomass burning(32%)comparable to secondary sulfate(34%)and mixed dust and traffic sources(26%).These findings demonstrate that both regional and local sources con-tribute to severe haze,highlighting the need for integrated policies for cross-border cooperation as well as stricter regulations to reduce biomass burning in Northern Thailand and Southeast Asia.展开更多
Electron–hole(e–h)recombination is a fundamental process that governs energy dissipation and device efficiency in semiconductors.In two-dimensional(2D)materials,the formation of tightly bound excitons makes exciton-...Electron–hole(e–h)recombination is a fundamental process that governs energy dissipation and device efficiency in semiconductors.In two-dimensional(2D)materials,the formation of tightly bound excitons makes exciton-mediated e–h recombination the dominant decay pathway.In this work,nonradiative e–h recombination within excitons in monolayer MoS2 is investigated using first-principles simulations that combine nonadiabatic molecular dynamics with𝐺𝑊and real-time Bethe–Salpeter equation(BSE)propagation.A two-step process is identified:rapid intervalley redistribution induced by exchange interaction,followed by slower phonon-assisted recombination facilitated by exciton binding.By selectively removing the screened Coulomb and exchange terms from the BSE Hamiltonian,their respective contributions are disentangled—exchange interaction is found to increase the number of accessible recombination pathways,while binding reduces the excitation energy and enhances nonradiative decay.A reduction in recombination lifetime by over an order of magnitude is observed due to the excitonic many-body effects.These findings provide microscopic insights for understanding and tuning exciton lifetimes in 2D transition-metal dichalcogenides.展开更多
Since Hermann Staudinger coined the revolutionary concept of macromolecules in 1920, synthetic polymers have served as a major game changer to our society and become indispensable in our daily lives. Unlike biomacromo...Since Hermann Staudinger coined the revolutionary concept of macromolecules in 1920, synthetic polymers have served as a major game changer to our society and become indispensable in our daily lives. Unlike biomacromolecules (e.g., DNA and proteins) possessing precise molar masses/chain sequences/topologies and specific biological functions, synthetic polymers are abiotic materials characterized by broad chain length distributions and undefined sequences. To bridge the gap between natural and synthetic polymers, the biomimetic synthesis of polymers with precise chain length, sequences and topologies has been long pursued and yet unmet in polymer science.展开更多
Wet deposition was collected in Mexico City (MC), Metropolitan Area of Monterrey (MAM) and El Chico National Park (ECNP), during 2009 and 2010. pH, conductivity, Cl-, , Na+, K+, Ca2+ and Mg2+ were determined. In MC, s...Wet deposition was collected in Mexico City (MC), Metropolitan Area of Monterrey (MAM) and El Chico National Park (ECNP), during 2009 and 2010. pH, conductivity, Cl-, , Na+, K+, Ca2+ and Mg2+ were determined. In MC, sulphate levels were greater than nitrate levels, and NH4 had mixed sources (vehicular emissions and agriculture activities). MAM had markedly alkaline atmospheric deposition, Na+ and Cl-levels were unexpectedly high, especially during hurricane “Alex”. Low pH values were found in ECNP and nitrate concentrations were high, suggesting the influence of a local source (forest fires). Deposition fluxes (Kg.ha-1yr-1) for N-NO3, N-NH4 and S-SO4 were 1.36, 2.74 and 4.84 for MAM;7.27, 0.57 and 4.32 for ECNP;and 5.97, 4.96 and 6.78 for MC, respectively. Nitrogen deposition fluxes in ECNP were high considering that this site is a natural reserve.展开更多
Considering the frequent use of netupitant in polytherapy,the elucidation of its oxidative metabolization pattern is of major importance.However,there is a lack of published research on the redox behavior of this nove...Considering the frequent use of netupitant in polytherapy,the elucidation of its oxidative metabolization pattern is of major importance.However,there is a lack of published research on the redox behavior of this novel neurokinin-1 receptor antagonist.Therefore,this study was performed to simulate the intensive hepatic biotransformation of netupitant using an electrochemically driven method.Most of the known enzyme-mediated reactions occurring in the liver(i.e.,N-dealkylation,hydroxylation,and Noxidation)were successfully mimicked by the electrolytic cell using a boron-doped diamond working electrode.The products were separated by reversed-phase high-performance liquid chromatography and identified by high-resolution mass spectrometry.Aside from its ability to pinpoint formerly unknown metabolites that could be responsible for the known side effects of netupitant or connected with any new perspective concerning future therapeutic indications,this electrochemical process also represents a facile alternative for the synthesis of oxidation products for further in vitro and in vivo studies.展开更多
The ternary solid complex was synthesized with sodium diethyldithiocarbamate (NaEt_2dtc), 1,10-phenanthroline (phen) and low hydrated dysprosium chloride in absolute ethanol by improved method of reference. The title ...The ternary solid complex was synthesized with sodium diethyldithiocarbamate (NaEt_2dtc), 1,10-phenanthroline (phen) and low hydrated dysprosium chloride in absolute ethanol by improved method of reference. The title complex was identified as the general formula of Dy(Et_2dtc)_3(phen) by chemical and elemental analyses. IR spectrum of the complex shows that the Dy^(3+) coordinated with six sulfur atoms of three NaEt_2dtc and two nitrogen atoms of phen. It is assumed that the coordination number of Dy^(3+) is eight.The enthalpy change of liquid-phase reaction of formation, Δ_rH~θ_m(l), is determined as (-19.091±0.015) kJ·mol^(-1) at 298.15 K by a microcalorimeter, and the enthalpy change of the solid-phase reaction of formation, Δ_rH~θ_m(s), is calculated as (139.641±0.482) kJ·mol^(-1) on the basis of a thermochemical cycle. The thermodynamic of reaction of formation was studied by changing the temperature of liquid-phase reaction. The constant-volume combustion energy of the complex, Δ_cU, is determined as (-16730.21±9.25) kJ·mol^(-1) by a precise rotating-bomb calorimeter at 298.15 K. Its standard enthalpies of combustion, Δ_cH~θ_m, and standard enthalpies of formation, Δ_fH~θ_m, are calculated as (-16749.42±9.25) kJ·mol^(-1) and (-2019.68±10.19) kJ·mol^(-1), respectively.展开更多
Rice is a grass seed from Oryza glaberrima species also known as the African rice.In Kenya,rice is mostly grown in Central(Mwea)and Nyanza(Ahero,West Kano,Migori and Kuria)areas.Milling rice produces rice husks as by-...Rice is a grass seed from Oryza glaberrima species also known as the African rice.In Kenya,rice is mostly grown in Central(Mwea)and Nyanza(Ahero,West Kano,Migori and Kuria)areas.Milling rice produces rice husks as by-products which can be sources of valuable chemical products(silica gel,sodium silicate).In trials to produce silica gel from rice husks,rice husks were charred in a combustion chamber(30 min)then ashed in a Muffle furnace(Advantec KL-420)at different temperatures.The ashes were then leached with distilled water/acids to remove metal oxides.Sixty grams(60 g)of the leached RHA(Rice Husk Ash)was mixed with 300 mL of 3 M NaOH solution in a Pyrex 500 mL beaker and boiled at 100℃(1 h).The silica gel samples were characterized using several methods.Elemental analysis was done using TXRF(Total X-Ray Fluorescence),while FTIR(Fourier-Transform Infrared Spectroscopy)was used to obtain an infrared spectrum of absorption of the silica sample.Results of the analysis conform to local and international quality standards.The rice husks had an average moisture content of 7.07%and 1.00-2.00 mm diameter.And 1.74%of the rice husk had pore sizes of about 0.710 mm.The average ash content was 22.65%.At 600℃,leaching with water yielded 98.2%silica compared with 99.1%(H2SO4)and 96.9%(HCl).At 500℃,leaching with HCl/H2SO4 causes a decrease.At 500℃,the availability of SiO2 is more for water leached samples.At 400℃,water leaching gave 98.49%silica while HCl leaching was 97.85%silica and H2SO4 was 99.41%.Silica is a precursor of silica gel.Statistical analyses imply water leaching RHA instead of acid leaching at 500℃ will produce a significant amount of silica gel.The open burn samples produced equal or better SiO2(silica gel precursor)yields compared with the incineration samples.FTIR analysis of the silica gel sample compared well with adsorption peaks of silica gel in literature.XRD(X-Ray Diffraction)analysis produced a pattern consistent with other XRD patterns of silica gel published by other researchers.展开更多
Mixture of phosphoric and sulfuric acid solutions has been used to investigate the dissolution of natural phosphates (PN) by DRC. The effect of concentration, particle size and stirring speed reaction is examined. The...Mixture of phosphoric and sulfuric acid solutions has been used to investigate the dissolution of natural phosphates (PN) by DRC. The effect of concentration, particle size and stirring speed reaction is examined. Thermochimique properties of each kinetic parameters reaction are determined. It was found that these parameters have a considerable effect on the thermochemical aspect of the attack reaction. It is known that the process of PN sulphophosphoric acid attack leads to the formation of dihydrate (CaSO4.2H2O: DH). The present work shows the precipitation of other residues their formula depends on factors studied. The increase in concentration leads to the formation of hemihydrate (CaSO4v1/2H2O:HH) beside DH for the low values of% H2SO4 due to the solubility of dihydrate on the etching solution and the precipitation of (Ca (H2PO4)2.2H2O) next of DH for low agitation values because of the lack of turbulence between the liquid phase and the solid phase which favors the precipitation of this latter compound.展开更多
In the present paper the isolation and characterization of seven major glycolipid classes (stigmasterol, acylated stigmasteryl glucoside, stigmasteryl glucoside, monogalactosyldiacylglycerol, digalactosyldiacylglycero...In the present paper the isolation and characterization of seven major glycolipid classes (stigmasterol, acylated stigmasteryl glucoside, stigmasteryl glucoside, monogalactosyldiacylglycerol, digalactosyldiacylglycerol, cerebroside and glucocerebroside) from Drymaria cordata (Linn.) Willd (Caryophyllaceae Family) are reported after an attempt has been made to congregate the traditional and pharmacological studies done on this important medicinal plant. Drymaria cordata is a weak spreading herb found widely dispersed in damp places all over the tropics of Africa, Asia and the Americas. There are many reports on its folk and traditional uses that include snake bite, skin diseases, peptic ulcer, headaches or nephritis, female infertility, sleeping disorders, convulsions, and febrile conditions in children. The plant has been examined on the basis of scientific in vitro and in vivo evaluations possessing the major pharmacological activities that include analgesic activity, antitussive activity, anxiolytic activity, antipyretic activity, antinociceptive activity, anti-inflammatory and antibacterial activities. The information summarized here is intended to serve as a reference tool for practitioners in the fields of ethnopharmacology, natural product chemistry and drug discovery related research.展开更多
In the last few decades,there has been a rapid emergence and growing interest in synthetic macrocyclic arenes,such as calixarenes[1,2],cyclophanes[3],cyclotriveratrylenes[4],pillararenes[5-7],and other novel macrocycl...In the last few decades,there has been a rapid emergence and growing interest in synthetic macrocyclic arenes,such as calixarenes[1,2],cyclophanes[3],cyclotriveratrylenes[4],pillararenes[5-7],and other novel macrocyclic arenes[8-10].These molecules have garnered significant attention in supramolecular chemistry for their fascinating structures,intrinsic cavities,ease of structural and property modifications and wide range of applications[11-14].展开更多
PVDF-based nanocomposites have gained significant focus in capacitors for their excellent dielectric strength, its multi-scale structural inhomogeneity is the bottleneck for improving the energy storage performance. H...PVDF-based nanocomposites have gained significant focus in capacitors for their excellent dielectric strength, its multi-scale structural inhomogeneity is the bottleneck for improving the energy storage performance. Here, the composite components are optimized by the matrix modification,BST(Ba_(0.6)Sr_(0.4)TiO_(3)) ceramic fibrillation and surface coating. A series of PVDF/polymethyl methacrylate/lysozyme@BST nanofibers with continuous gradient distribution(PF-M/m BST nf-g) are prepared by the concentration gradient-biaxial high-speed electrospinning. The finite element simulation and experiment results indicate that the continuous gradient structure is favorable for the microstructure and inhomogeneity of the electric field distribution, significantly increasing the breakdown strength(Eb) and the permittivity(εr), as well as effectively suppressing the interfacial injected charge and leakage current. As a result, the energy storage density(Ue) of 23.1 J/cm^(3)at 600 MV/m with the charge-discharge efficiency(η) of 71% is achieved compared to PF-M(5.6 J/cm^(3)@350 MV/m, 65%). The exciting energy storage performance based on the well-designed PF-M/m BST nf-g provides important information for the development and application of polymer nanocomposite dielectrics.展开更多
Aqueous organic redox flow batteries(AORFBs)exploit the reversible electrochemical reactions of watersoluble organic redox-active species to store electricity and have emerged as promising electrochemical energy stora...Aqueous organic redox flow batteries(AORFBs)exploit the reversible electrochemical reactions of watersoluble organic redox-active species to store electricity and have emerged as promising electrochemical energy storage technologies.To improve the battery performance related to the cell resistance,such as the power density and energy efficiency,it is essential to understand the cell resistance and determine the major contributor.Here,we conduct comprehensive electrochemical impedance spectroscopy(EIS)studies and cell polarization on a representative TEMPTMA/MV cell assembled with a commercial AMVN membrane and probe the proportion of the ohmic resistance to the total cell resistance at various stages of charge(SOCs)ranging from 10%to 100%.At 0 mA·cm^(−2),the ohmic resistance is responsible for 60.3%–71.7%of the resistance of the entire cell,whereas at high current densities(for example,when the power density reaches the maximum),the ohmic resistance still contributes 47.9%–61.4%.Our quantitative analysis highlights the dominance of the ohmic resistance and anticipates that a membrane with lower resistivity may significantly increase the power density.展开更多
Ultrafine,highly dispersed Pt clusters were immobilized onto the Co nanoparticle surfaces by one-step pyrolysis of the precursor Pt(Ⅱ)-encapsulating Co-MOF-74.Owing to the small size effects of Pt clusters as well as...Ultrafine,highly dispersed Pt clusters were immobilized onto the Co nanoparticle surfaces by one-step pyrolysis of the precursor Pt(Ⅱ)-encapsulating Co-MOF-74.Owing to the small size effects of Pt clusters as well as the strongly enhanced synergistic interactions between Pt and Co atoms,the obtained Pt-on-Co/C400 catalysts exhib-ited excellent catalytic activity toward the hydrolysis of ammonia borane with an extremely high turnover frequency(TOF)value of 3022 min^(-1)at 303 K.Durability test indicated that the obtained Pt-on-Co/C400 catalysts possessed high catalytic stability,and there were no changes in the catalyst structures and catalytic activities after 10 cycles.展开更多
The search for mechanical properties of materials reached a highly acclaimed level, when indentations could be analysed on the basis of elastic theory for hardness and elastic modulus. The mathematical formulas proved...The search for mechanical properties of materials reached a highly acclaimed level, when indentations could be analysed on the basis of elastic theory for hardness and elastic modulus. The mathematical formulas proved to be very complicated, and various trials were published between the 1900s and 2000s. The development of indentation instruments and the wish to make the application in numerous steps easier, led in 1992 to trials with iterations by using relative values instead of absolute ones. Excessive iterations of computers with 3 + 8 free parameters of the loading and unloading curves became possible and were implemented into the instruments and worldwide standards. The physical formula for hardness was defined as force over area. For the conical, pyramidal, and spherical indenters, one simply took the projected area for the calculation of the indentation depth from the projected area, adjusted it later by the iterations with respect to fused quartz or aluminium as standard materials, and called it “contact height”. Continuously measured indentation loading curves were formulated as loading force over depth square. The unloading curves after release of the indenter used the initial steepness of the pressure relief for the calculation of what was (and is) incorrectly called “Young’s modulus”. But it is not unidirectional. And for the spherical indentations’ loading curve, they defined the indentation force over depth raised to 3/2 (but without R/h correction). They till now (2025) violate the energy law, because they use all applied force for the indenter depth and ignore the obvious sidewise force upon indentation (cf. e.g. the wood cleaving). The various refinements led to more and more complicated formulas that could not be reasonably calculated with them. One decided to use 3 + 8 free-parameter iterations for fitting to the (poor) standards of fused quartz or aluminium. The mechanical values of these were considered to be “true”. This is till now the worldwide standard of DIN-ISO-ASTM-14577, avoiding overcomplicated formulas with their complexity. Some of these are shown in the Introduction Section. By doing so, one avoided the understanding of indentation results on a physical basis. However, we open a simple way to obtain absolute values (though still on the blackbox instrument’s unsuitable force calibration). We do not iterate but calculate algebraically on the basis of the correct, physically deduced exponent of the loading force parabolas with h3/2 instead of false “h2” (for the spherical indentation, there is a calotte-radius over depth correction), and we reveal the physical errors taken up in the official worldwide “14577-Standard”. Importantly, we reveal the hitherto fully overlooked phase transitions under load that are not detectable with the false exponent. Phase-transition twinning is even present and falsifies the iteration standards. Instead of elasticity theory, we use the well-defined geometry of these indentations. By doing so, we reach simple algebraically calculable formulas and find the physical indentation hardness of materials with their onset depth, onset force and energy, as well as their phase-transition energy (temperature dependent also its activation energy). The most important phase transitions are our absolute algebraically calculated results. The now most easily obtained phase transitions under load are very dangerous because they produce polymorph interfaces between the changed and the unchanged material. It was found and published by high-enlargement microscopy (5000-fold) that these trouble spots are the sites for the development of stable, 1 to 2 µm long, micro-cracks (stable for months). If however, a force higher than the one of their formation occurs to them, these grow to catastrophic crash. That works equally with turbulences at the pickle fork of airliners. After the publication of these facts and after three fatal crashing had occurred in a short sequence, FAA (Federal Aviation Agency) reacted by rechecking all airplanes for such micro cracks. These were now found in a new fleet of airliners from where the three crashed ones came. These were previously overlooked. FAA became aware of that risk and grounded 290 (certainly all) of them, because the material of these did not have higher phase-transition onset and energy than other airplanes with better material. They did so despite the 14577-Standard that does not find (and thus formally forbids) phase transitions under indenter load with the false exponent on the indentation parabola. However, this “Standard” will, despite the present author’s well-founded petition, not be corrected for the next 5 years.展开更多
Abstract:In today’s economy,determining accessible and affordable techniques to remove Heavy Metals(HMs)from wastewater is crucial.Activated carbon is highly effective in adsorbing HMs due to its large surface area a...Abstract:In today’s economy,determining accessible and affordable techniques to remove Heavy Metals(HMs)from wastewater is crucial.Activated carbon is highly effective in adsorbing HMs due to its large surface area and porous structure.It works by attracting and binding HM ions to its surface.Okoubaka is known for its medicinal properties and some studies suggest it has detoxifying effects.However,its specific role in HM removal would likely involve binding mechanisms like other plant-based materials.This study examines the efficiency of activated charcoal,charred versus uncharred Okoubaka plant materials,eggshells and oxalic acid to remove HMs like copper,lead,and zinc from contaminated water.展开更多
Rare earth elements(REEs) were extracted from phosphogypsum(PG) using an indirect leaching method that produces CaCO_(3).The carbonation process transforms PG into CaCO_(3),and a potential source of value is the(NH_(4...Rare earth elements(REEs) were extracted from phosphogypsum(PG) using an indirect leaching method that produces CaCO_(3).The carbonation process transforms PG into CaCO_(3),and a potential source of value is the(NH_(4))_(2)SO_(4) fertilizer.The calcium carbonate byproduct is rich in REEs that are originally present in PG.Calcium carbonate,a byproduct of PG carbonation and a rich source of REEs,could dissolve in nitric acid to produce a calcium nitrate leach solution that contains RE nitrate.Subsequently,the most widely used solvent extraction technique can make use of an environmentally benign nitrate ionic liquid.Cyphos IL 101(trihexyl(tetradecyl)phosphonium chloride) is transformed into trihexyl(tetradecyl)phosphonium nitrate([P_(66614)][NO_(3)]) ionic liquid by adding 2.5 mol/L potassium nitrate.The extraction examinations were tested by equilibration of 2 mL of [P_(66614)][NO_(3)] with 2 mL of a synthetic solution of 1000 mg/L of individual La,Ce,and Nd to gain the optimal extraction conditions.The high extraction efficiency of La,Ce,and Nd was gained by stirring a 1/1 aqueous/organic phase ratio and 3 mol/L NH_(4)NO_(3)(as salting out) at 800 r/min for 40 min at 50℃ to decrease the viscosity of [P_(66614)][NO_(3)].The La(Ⅲ),Ce(Ⅲ),and Nd(Ⅲ) stripping efficiencies were examined from their loaded [P_(66614)][NO_(3)] ionic liquid by 1/1 A/O ratio of acidified water,800 r/min stirring speed,and 25℃.After nine cycles,the extraction and stirring efficiency for the La,Ce,and Nd drop to about 80%.The extraction and stripping parameters are applied to the RE leachate from PG to gain the RE oxide with an assay of 92.67%.展开更多
Zeolites are crystalline microporous materials widely used in catalysis,adsorption,and ion exchange owing to their tunable pore structures and acid centers[1].Traditional zeolites,however,often suffer from limitations...Zeolites are crystalline microporous materials widely used in catalysis,adsorption,and ion exchange owing to their tunable pore structures and acid centers[1].Traditional zeolites,however,often suffer from limitations such as restricted molecular diffusion and rapid coking,which hinder their efficiency in processing large molecules.展开更多
In the present study,different structured,Mg-7Gd-4Y-1Zn-0.2Zr(GWZ)and Mg-3Zn-1Al-1Ca-0.5Mn(ZA)alloys based bi-metal composites were fabricated through extrusion.In particular,we reported that the strong and large diff...In the present study,different structured,Mg-7Gd-4Y-1Zn-0.2Zr(GWZ)and Mg-3Zn-1Al-1Ca-0.5Mn(ZA)alloys based bi-metal composites were fabricated through extrusion.In particular,we reported that the strong and large diffusional interfacial thickness comprised of fine grains along with the segregation of the different elements at the interfacial region transferred the load to the base of the composite,and hence acted like a bonder and increased the stability of the interfaces.Most specifically,the rare“composite texture”having c-axes//radial direction(RD)and tilted c-axes//extruded direction(ED)with very low texture intensities was developed in all composites,which is the key requirement for retaining high strength and high ductility.The microstructure of GWZ Mg alloy consists of dense lamellar LPSO_(s),blocky LPSO_(s),rod-shaped LPSO_(s),Mg-enriched rare earth(RE)precipitates,and broken square-shaped RE-enriched precipitates.In contrast,the microstructure of ZA Mg alloy is comprised of MgAl_(2)Ca laves,different-shaped Al_(8)Mn_(5),and nano-sized Mg_(17)Al_(12) precipitates.Particularly,after extrusion,the strongly bonded interfacial region was decorated by Al,Ca,Gd,Y,and Zr elements.The WAW bi-metal composite showed a wavy interfacial morphology compared to the AWA and AW bi-metal composites and the diffusional thickness for all composites was quite large(>20μm).Therefore,based on the above brief discussion,the AWA bi-metal composite(having HAGBs>93%),exhibited exceptionally high performance.The elongation to fracture and strength under compression was significantly higher(EF∼50%,UCS∼17.70%)compared to the GWZ Mg alloy.Likewise,the bendability of the AWA bi-metal composite was much higher(∼103.2%)than the GWZ Mg alloy and higher than other composites.Therefore,the fabrication of bi-metal composites is a practical approach in achieving strength and ductility.展开更多
基金Open access funding provided by The Science,Technology&Innovation Funding Authority(STDF)in cooperation with The Egyp-tian Knowledge Bank(EKB).
文摘The increasing demand for sustainable energy storage solutions has intensified the focus on high-performance supercapaci-tors,known for their rapid charge/discharge capabilities,high power density,and long cycle life.Polyurethane(PU)-based materials have gained attention as promising candidates for supercapacitor electrodes,due to their flexibility,mechanical robustness,and tunable properties.It is important to clarify that PU typically does not contribute directly to charge storage via adsorption or pseudocapacitive mechanisms.Instead,PU serves as a flexible scaffold,a binder,or a precursor for the preparation of heteroatom-doped carbon materials upon thermal treatment.Thus,the term'PU-based'in this review refers to PU-supported or PU-derived composites,where PU enables structural or functional integration of active electrode Materi-als.Polyurethane composites incorporating graphene oxide have demonstrated a specific capacitance of 758.8 mF/cm^(2)with capacitance retention of 92%over 5,000 cycles.Other PU-based electrodes have achieved energy densities up to 22.5 Wh/kg and power densities of 1472.7 W/kg,reflecting their potential for high-performance energy storage applications.Despite these advantages,challenges,such as low intrinsic conductivity and the environmental impact of traditional synthesis methods,limit their widespread adoption.Conventional PU composites often incorporate conductive additives like carbon materi-als,metal oxides,or conductive polymers to enhance their electrochemical performance,yet these approaches may involve non-renewable or toxic components.Developing green energy materials that adhere to sustainability and green chemistry principles is crucial to address these limitations.This includes using renewable resources,environmentally friendly process-ing techniques,and recyclable materials to reduce the ecological footprint and meet the growing need for sustainable energy storage technologies.This review highlights current trends in developing eco-friendly supercapacitor materials,addressing key challenges such as limited conductivity and complex processing.It uniquely integrates green chemistry principles with advances in polyurethane composites,emphasizing sustainable feedstocks,heteroatom doping,and functional nanomateri-als.By combining these aspects,this review provides a comprehensive perspective not fully covered in existing literature.
文摘Annual haze in Northern Thailand has become increasingly severe,impacting health and the environment.How-ever,the sources of the haze remain poorly quantified due to limited observational data on aerosol molecular tracers.This study comprehensively investigates chemical composition of PM_(2.5),including both inorganic and organic compounds throughout haze and post-haze periods in 2019 at a rural site of Northern Thailand.Average PM_(2.5) concentrations during haze and post-haze period were 87±36 and 21±11μg/m^(3),respectively.Organic matter was the dominant contributor in PM_(2.5) mass,followed by water soluble inorganic ions and mineral dust.Molecular markers,including levoglucosan,dehydroabietic acid,and 4-nitrocatechol,and ions(Cl^(-),and K^(+)),were used to characterize low haze(PM_(2.5)<100μg/m^(3))and episodic haze(PM_(2.5)>100μg/m^(3)).Low haze is associated with local aerosols from agricultural waste burning,while episodic haze is linked to aged aerosols from mixed agricultural waste,softwood,and hardwood burning.Source apportionment incorporating these molecular markers in receptor modelling(Positive matrix factorization),identified three distinct biomass burning sources:mixed,local,and aged biomass burnings,contributing 31,19 and 13%of PM_(2.5) during haze period.During post-haze period,contributions shifted,with local biomass burning(32%)comparable to secondary sulfate(34%)and mixed dust and traffic sources(26%).These findings demonstrate that both regional and local sources con-tribute to severe haze,highlighting the need for integrated policies for cross-border cooperation as well as stricter regulations to reduce biomass burning in Northern Thailand and Southeast Asia.
基金supported by the National Key Research and Development Program of China (Grant Nos.2024YFA1409800 for J.Z.and2024YFA1408603 for Q.Z.)the National Natural Science Foundation of China (Grant Nos.12125408,12334004for J.Z.,and 12174363 for Q.Z.)+1 种基金the Innovation Program for Quantum Science and Technology (Grant No.2021ZD0303306 for J.Z.)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB0450101 for J.Z.)。
文摘Electron–hole(e–h)recombination is a fundamental process that governs energy dissipation and device efficiency in semiconductors.In two-dimensional(2D)materials,the formation of tightly bound excitons makes exciton-mediated e–h recombination the dominant decay pathway.In this work,nonradiative e–h recombination within excitons in monolayer MoS2 is investigated using first-principles simulations that combine nonadiabatic molecular dynamics with𝐺𝑊and real-time Bethe–Salpeter equation(BSE)propagation.A two-step process is identified:rapid intervalley redistribution induced by exchange interaction,followed by slower phonon-assisted recombination facilitated by exciton binding.By selectively removing the screened Coulomb and exchange terms from the BSE Hamiltonian,their respective contributions are disentangled—exchange interaction is found to increase the number of accessible recombination pathways,while binding reduces the excitation energy and enhances nonradiative decay.A reduction in recombination lifetime by over an order of magnitude is observed due to the excitonic many-body effects.These findings provide microscopic insights for understanding and tuning exciton lifetimes in 2D transition-metal dichalcogenides.
文摘Since Hermann Staudinger coined the revolutionary concept of macromolecules in 1920, synthetic polymers have served as a major game changer to our society and become indispensable in our daily lives. Unlike biomacromolecules (e.g., DNA and proteins) possessing precise molar masses/chain sequences/topologies and specific biological functions, synthetic polymers are abiotic materials characterized by broad chain length distributions and undefined sequences. To bridge the gap between natural and synthetic polymers, the biomimetic synthesis of polymers with precise chain length, sequences and topologies has been long pursued and yet unmet in polymer science.
文摘Wet deposition was collected in Mexico City (MC), Metropolitan Area of Monterrey (MAM) and El Chico National Park (ECNP), during 2009 and 2010. pH, conductivity, Cl-, , Na+, K+, Ca2+ and Mg2+ were determined. In MC, sulphate levels were greater than nitrate levels, and NH4 had mixed sources (vehicular emissions and agriculture activities). MAM had markedly alkaline atmospheric deposition, Na+ and Cl-levels were unexpectedly high, especially during hurricane “Alex”. Low pH values were found in ECNP and nitrate concentrations were high, suggesting the influence of a local source (forest fires). Deposition fluxes (Kg.ha-1yr-1) for N-NO3, N-NH4 and S-SO4 were 1.36, 2.74 and 4.84 for MAM;7.27, 0.57 and 4.32 for ECNP;and 5.97, 4.96 and 6.78 for MC, respectively. Nitrogen deposition fluxes in ECNP were high considering that this site is a natural reserve.
基金The authors gratefully acknowledged the financial support for part of this work by the German Research Foundation(DFG,Grant No.:KA 1093/7-2,Bonn,Germany)as well as Iuliu Hațieganu University(Internal Grant No.:5200/19/01.03.2017)a grant of the Romanian Ministry of Education and Research,CCCDI-UEFISCDI(Project No.:PNe-Ⅲ-P2-2.1-PED-2019-5473)within PNCDIⅢ.
文摘Considering the frequent use of netupitant in polytherapy,the elucidation of its oxidative metabolization pattern is of major importance.However,there is a lack of published research on the redox behavior of this novel neurokinin-1 receptor antagonist.Therefore,this study was performed to simulate the intensive hepatic biotransformation of netupitant using an electrochemically driven method.Most of the known enzyme-mediated reactions occurring in the liver(i.e.,N-dealkylation,hydroxylation,and Noxidation)were successfully mimicked by the electrolytic cell using a boron-doped diamond working electrode.The products were separated by reversed-phase high-performance liquid chromatography and identified by high-resolution mass spectrometry.Aside from its ability to pinpoint formerly unknown metabolites that could be responsible for the known side effects of netupitant or connected with any new perspective concerning future therapeutic indications,this electrochemical process also represents a facile alternative for the synthesis of oxidation products for further in vitro and in vivo studies.
文摘The ternary solid complex was synthesized with sodium diethyldithiocarbamate (NaEt_2dtc), 1,10-phenanthroline (phen) and low hydrated dysprosium chloride in absolute ethanol by improved method of reference. The title complex was identified as the general formula of Dy(Et_2dtc)_3(phen) by chemical and elemental analyses. IR spectrum of the complex shows that the Dy^(3+) coordinated with six sulfur atoms of three NaEt_2dtc and two nitrogen atoms of phen. It is assumed that the coordination number of Dy^(3+) is eight.The enthalpy change of liquid-phase reaction of formation, Δ_rH~θ_m(l), is determined as (-19.091±0.015) kJ·mol^(-1) at 298.15 K by a microcalorimeter, and the enthalpy change of the solid-phase reaction of formation, Δ_rH~θ_m(s), is calculated as (139.641±0.482) kJ·mol^(-1) on the basis of a thermochemical cycle. The thermodynamic of reaction of formation was studied by changing the temperature of liquid-phase reaction. The constant-volume combustion energy of the complex, Δ_cU, is determined as (-16730.21±9.25) kJ·mol^(-1) by a precise rotating-bomb calorimeter at 298.15 K. Its standard enthalpies of combustion, Δ_cH~θ_m, and standard enthalpies of formation, Δ_fH~θ_m, are calculated as (-16749.42±9.25) kJ·mol^(-1) and (-2019.68±10.19) kJ·mol^(-1), respectively.
文摘Rice is a grass seed from Oryza glaberrima species also known as the African rice.In Kenya,rice is mostly grown in Central(Mwea)and Nyanza(Ahero,West Kano,Migori and Kuria)areas.Milling rice produces rice husks as by-products which can be sources of valuable chemical products(silica gel,sodium silicate).In trials to produce silica gel from rice husks,rice husks were charred in a combustion chamber(30 min)then ashed in a Muffle furnace(Advantec KL-420)at different temperatures.The ashes were then leached with distilled water/acids to remove metal oxides.Sixty grams(60 g)of the leached RHA(Rice Husk Ash)was mixed with 300 mL of 3 M NaOH solution in a Pyrex 500 mL beaker and boiled at 100℃(1 h).The silica gel samples were characterized using several methods.Elemental analysis was done using TXRF(Total X-Ray Fluorescence),while FTIR(Fourier-Transform Infrared Spectroscopy)was used to obtain an infrared spectrum of absorption of the silica sample.Results of the analysis conform to local and international quality standards.The rice husks had an average moisture content of 7.07%and 1.00-2.00 mm diameter.And 1.74%of the rice husk had pore sizes of about 0.710 mm.The average ash content was 22.65%.At 600℃,leaching with water yielded 98.2%silica compared with 99.1%(H2SO4)and 96.9%(HCl).At 500℃,leaching with HCl/H2SO4 causes a decrease.At 500℃,the availability of SiO2 is more for water leached samples.At 400℃,water leaching gave 98.49%silica while HCl leaching was 97.85%silica and H2SO4 was 99.41%.Silica is a precursor of silica gel.Statistical analyses imply water leaching RHA instead of acid leaching at 500℃ will produce a significant amount of silica gel.The open burn samples produced equal or better SiO2(silica gel precursor)yields compared with the incineration samples.FTIR analysis of the silica gel sample compared well with adsorption peaks of silica gel in literature.XRD(X-Ray Diffraction)analysis produced a pattern consistent with other XRD patterns of silica gel published by other researchers.
文摘Mixture of phosphoric and sulfuric acid solutions has been used to investigate the dissolution of natural phosphates (PN) by DRC. The effect of concentration, particle size and stirring speed reaction is examined. Thermochimique properties of each kinetic parameters reaction are determined. It was found that these parameters have a considerable effect on the thermochemical aspect of the attack reaction. It is known that the process of PN sulphophosphoric acid attack leads to the formation of dihydrate (CaSO4.2H2O: DH). The present work shows the precipitation of other residues their formula depends on factors studied. The increase in concentration leads to the formation of hemihydrate (CaSO4v1/2H2O:HH) beside DH for the low values of% H2SO4 due to the solubility of dihydrate on the etching solution and the precipitation of (Ca (H2PO4)2.2H2O) next of DH for low agitation values because of the lack of turbulence between the liquid phase and the solid phase which favors the precipitation of this latter compound.
文摘In the present paper the isolation and characterization of seven major glycolipid classes (stigmasterol, acylated stigmasteryl glucoside, stigmasteryl glucoside, monogalactosyldiacylglycerol, digalactosyldiacylglycerol, cerebroside and glucocerebroside) from Drymaria cordata (Linn.) Willd (Caryophyllaceae Family) are reported after an attempt has been made to congregate the traditional and pharmacological studies done on this important medicinal plant. Drymaria cordata is a weak spreading herb found widely dispersed in damp places all over the tropics of Africa, Asia and the Americas. There are many reports on its folk and traditional uses that include snake bite, skin diseases, peptic ulcer, headaches or nephritis, female infertility, sleeping disorders, convulsions, and febrile conditions in children. The plant has been examined on the basis of scientific in vitro and in vivo evaluations possessing the major pharmacological activities that include analgesic activity, antitussive activity, anxiolytic activity, antipyretic activity, antinociceptive activity, anti-inflammatory and antibacterial activities. The information summarized here is intended to serve as a reference tool for practitioners in the fields of ethnopharmacology, natural product chemistry and drug discovery related research.
文摘In the last few decades,there has been a rapid emergence and growing interest in synthetic macrocyclic arenes,such as calixarenes[1,2],cyclophanes[3],cyclotriveratrylenes[4],pillararenes[5-7],and other novel macrocyclic arenes[8-10].These molecules have garnered significant attention in supramolecular chemistry for their fascinating structures,intrinsic cavities,ease of structural and property modifications and wide range of applications[11-14].
基金the support and funding from the National Natural Science Foundation of China (Nos. 51773164, 5186020071)Ningxia Natural Science Foundation (No. 2023AAC03104)。
文摘PVDF-based nanocomposites have gained significant focus in capacitors for their excellent dielectric strength, its multi-scale structural inhomogeneity is the bottleneck for improving the energy storage performance. Here, the composite components are optimized by the matrix modification,BST(Ba_(0.6)Sr_(0.4)TiO_(3)) ceramic fibrillation and surface coating. A series of PVDF/polymethyl methacrylate/lysozyme@BST nanofibers with continuous gradient distribution(PF-M/m BST nf-g) are prepared by the concentration gradient-biaxial high-speed electrospinning. The finite element simulation and experiment results indicate that the continuous gradient structure is favorable for the microstructure and inhomogeneity of the electric field distribution, significantly increasing the breakdown strength(Eb) and the permittivity(εr), as well as effectively suppressing the interfacial injected charge and leakage current. As a result, the energy storage density(Ue) of 23.1 J/cm^(3)at 600 MV/m with the charge-discharge efficiency(η) of 71% is achieved compared to PF-M(5.6 J/cm^(3)@350 MV/m, 65%). The exciting energy storage performance based on the well-designed PF-M/m BST nf-g provides important information for the development and application of polymer nanocomposite dielectrics.
基金supported by the National Natural Science Foundation of China(22308345)the Anhui Provincial Natural Science Foundation(2308085QB68)the Fundamental Research Funds for the Central Universities(WK2060000059).
文摘Aqueous organic redox flow batteries(AORFBs)exploit the reversible electrochemical reactions of watersoluble organic redox-active species to store electricity and have emerged as promising electrochemical energy storage technologies.To improve the battery performance related to the cell resistance,such as the power density and energy efficiency,it is essential to understand the cell resistance and determine the major contributor.Here,we conduct comprehensive electrochemical impedance spectroscopy(EIS)studies and cell polarization on a representative TEMPTMA/MV cell assembled with a commercial AMVN membrane and probe the proportion of the ohmic resistance to the total cell resistance at various stages of charge(SOCs)ranging from 10%to 100%.At 0 mA·cm^(−2),the ohmic resistance is responsible for 60.3%–71.7%of the resistance of the entire cell,whereas at high current densities(for example,when the power density reaches the maximum),the ohmic resistance still contributes 47.9%–61.4%.Our quantitative analysis highlights the dominance of the ohmic resistance and anticipates that a membrane with lower resistivity may significantly increase the power density.
文摘Ultrafine,highly dispersed Pt clusters were immobilized onto the Co nanoparticle surfaces by one-step pyrolysis of the precursor Pt(Ⅱ)-encapsulating Co-MOF-74.Owing to the small size effects of Pt clusters as well as the strongly enhanced synergistic interactions between Pt and Co atoms,the obtained Pt-on-Co/C400 catalysts exhib-ited excellent catalytic activity toward the hydrolysis of ammonia borane with an extremely high turnover frequency(TOF)value of 3022 min^(-1)at 303 K.Durability test indicated that the obtained Pt-on-Co/C400 catalysts possessed high catalytic stability,and there were no changes in the catalyst structures and catalytic activities after 10 cycles.
文摘The search for mechanical properties of materials reached a highly acclaimed level, when indentations could be analysed on the basis of elastic theory for hardness and elastic modulus. The mathematical formulas proved to be very complicated, and various trials were published between the 1900s and 2000s. The development of indentation instruments and the wish to make the application in numerous steps easier, led in 1992 to trials with iterations by using relative values instead of absolute ones. Excessive iterations of computers with 3 + 8 free parameters of the loading and unloading curves became possible and were implemented into the instruments and worldwide standards. The physical formula for hardness was defined as force over area. For the conical, pyramidal, and spherical indenters, one simply took the projected area for the calculation of the indentation depth from the projected area, adjusted it later by the iterations with respect to fused quartz or aluminium as standard materials, and called it “contact height”. Continuously measured indentation loading curves were formulated as loading force over depth square. The unloading curves after release of the indenter used the initial steepness of the pressure relief for the calculation of what was (and is) incorrectly called “Young’s modulus”. But it is not unidirectional. And for the spherical indentations’ loading curve, they defined the indentation force over depth raised to 3/2 (but without R/h correction). They till now (2025) violate the energy law, because they use all applied force for the indenter depth and ignore the obvious sidewise force upon indentation (cf. e.g. the wood cleaving). The various refinements led to more and more complicated formulas that could not be reasonably calculated with them. One decided to use 3 + 8 free-parameter iterations for fitting to the (poor) standards of fused quartz or aluminium. The mechanical values of these were considered to be “true”. This is till now the worldwide standard of DIN-ISO-ASTM-14577, avoiding overcomplicated formulas with their complexity. Some of these are shown in the Introduction Section. By doing so, one avoided the understanding of indentation results on a physical basis. However, we open a simple way to obtain absolute values (though still on the blackbox instrument’s unsuitable force calibration). We do not iterate but calculate algebraically on the basis of the correct, physically deduced exponent of the loading force parabolas with h3/2 instead of false “h2” (for the spherical indentation, there is a calotte-radius over depth correction), and we reveal the physical errors taken up in the official worldwide “14577-Standard”. Importantly, we reveal the hitherto fully overlooked phase transitions under load that are not detectable with the false exponent. Phase-transition twinning is even present and falsifies the iteration standards. Instead of elasticity theory, we use the well-defined geometry of these indentations. By doing so, we reach simple algebraically calculable formulas and find the physical indentation hardness of materials with their onset depth, onset force and energy, as well as their phase-transition energy (temperature dependent also its activation energy). The most important phase transitions are our absolute algebraically calculated results. The now most easily obtained phase transitions under load are very dangerous because they produce polymorph interfaces between the changed and the unchanged material. It was found and published by high-enlargement microscopy (5000-fold) that these trouble spots are the sites for the development of stable, 1 to 2 µm long, micro-cracks (stable for months). If however, a force higher than the one of their formation occurs to them, these grow to catastrophic crash. That works equally with turbulences at the pickle fork of airliners. After the publication of these facts and after three fatal crashing had occurred in a short sequence, FAA (Federal Aviation Agency) reacted by rechecking all airplanes for such micro cracks. These were now found in a new fleet of airliners from where the three crashed ones came. These were previously overlooked. FAA became aware of that risk and grounded 290 (certainly all) of them, because the material of these did not have higher phase-transition onset and energy than other airplanes with better material. They did so despite the 14577-Standard that does not find (and thus formally forbids) phase transitions under indenter load with the false exponent on the indentation parabola. However, this “Standard” will, despite the present author’s well-founded petition, not be corrected for the next 5 years.
基金The Sherman Fairchild Foundation Undergraduate Research GrantThe National Science Foundation Award#1912400:HBCU-UP Implementation Project:Improving Minority Participation and Completion through STEM at Dillard University(IMPACTS@DU Ⅱ)Dillard University Endowed Professorship,funds。
文摘Abstract:In today’s economy,determining accessible and affordable techniques to remove Heavy Metals(HMs)from wastewater is crucial.Activated carbon is highly effective in adsorbing HMs due to its large surface area and porous structure.It works by attracting and binding HM ions to its surface.Okoubaka is known for its medicinal properties and some studies suggest it has detoxifying effects.However,its specific role in HM removal would likely involve binding mechanisms like other plant-based materials.This study examines the efficiency of activated charcoal,charred versus uncharred Okoubaka plant materials,eggshells and oxalic acid to remove HMs like copper,lead,and zinc from contaminated water.
文摘Rare earth elements(REEs) were extracted from phosphogypsum(PG) using an indirect leaching method that produces CaCO_(3).The carbonation process transforms PG into CaCO_(3),and a potential source of value is the(NH_(4))_(2)SO_(4) fertilizer.The calcium carbonate byproduct is rich in REEs that are originally present in PG.Calcium carbonate,a byproduct of PG carbonation and a rich source of REEs,could dissolve in nitric acid to produce a calcium nitrate leach solution that contains RE nitrate.Subsequently,the most widely used solvent extraction technique can make use of an environmentally benign nitrate ionic liquid.Cyphos IL 101(trihexyl(tetradecyl)phosphonium chloride) is transformed into trihexyl(tetradecyl)phosphonium nitrate([P_(66614)][NO_(3)]) ionic liquid by adding 2.5 mol/L potassium nitrate.The extraction examinations were tested by equilibration of 2 mL of [P_(66614)][NO_(3)] with 2 mL of a synthetic solution of 1000 mg/L of individual La,Ce,and Nd to gain the optimal extraction conditions.The high extraction efficiency of La,Ce,and Nd was gained by stirring a 1/1 aqueous/organic phase ratio and 3 mol/L NH_(4)NO_(3)(as salting out) at 800 r/min for 40 min at 50℃ to decrease the viscosity of [P_(66614)][NO_(3)].The La(Ⅲ),Ce(Ⅲ),and Nd(Ⅲ) stripping efficiencies were examined from their loaded [P_(66614)][NO_(3)] ionic liquid by 1/1 A/O ratio of acidified water,800 r/min stirring speed,and 25℃.After nine cycles,the extraction and stirring efficiency for the La,Ce,and Nd drop to about 80%.The extraction and stripping parameters are applied to the RE leachate from PG to gain the RE oxide with an assay of 92.67%.
基金the support of the National Natural Science Foundation of China(Nos.22205207 and 22378369).
文摘Zeolites are crystalline microporous materials widely used in catalysis,adsorption,and ion exchange owing to their tunable pore structures and acid centers[1].Traditional zeolites,however,often suffer from limitations such as restricted molecular diffusion and rapid coking,which hinder their efficiency in processing large molecules.
基金fully supported by the National Natural Science Foundation of China RFIS-1(52250410344 and 52250410343)the Deanship of Research and Graduate Studies at King Khalid University for funding this work through Large Research Project under grant number RGP2/277/45.
文摘In the present study,different structured,Mg-7Gd-4Y-1Zn-0.2Zr(GWZ)and Mg-3Zn-1Al-1Ca-0.5Mn(ZA)alloys based bi-metal composites were fabricated through extrusion.In particular,we reported that the strong and large diffusional interfacial thickness comprised of fine grains along with the segregation of the different elements at the interfacial region transferred the load to the base of the composite,and hence acted like a bonder and increased the stability of the interfaces.Most specifically,the rare“composite texture”having c-axes//radial direction(RD)and tilted c-axes//extruded direction(ED)with very low texture intensities was developed in all composites,which is the key requirement for retaining high strength and high ductility.The microstructure of GWZ Mg alloy consists of dense lamellar LPSO_(s),blocky LPSO_(s),rod-shaped LPSO_(s),Mg-enriched rare earth(RE)precipitates,and broken square-shaped RE-enriched precipitates.In contrast,the microstructure of ZA Mg alloy is comprised of MgAl_(2)Ca laves,different-shaped Al_(8)Mn_(5),and nano-sized Mg_(17)Al_(12) precipitates.Particularly,after extrusion,the strongly bonded interfacial region was decorated by Al,Ca,Gd,Y,and Zr elements.The WAW bi-metal composite showed a wavy interfacial morphology compared to the AWA and AW bi-metal composites and the diffusional thickness for all composites was quite large(>20μm).Therefore,based on the above brief discussion,the AWA bi-metal composite(having HAGBs>93%),exhibited exceptionally high performance.The elongation to fracture and strength under compression was significantly higher(EF∼50%,UCS∼17.70%)compared to the GWZ Mg alloy.Likewise,the bendability of the AWA bi-metal composite was much higher(∼103.2%)than the GWZ Mg alloy and higher than other composites.Therefore,the fabrication of bi-metal composites is a practical approach in achieving strength and ductility.
