We present an overview of some recent developments in the area of mathematical modeling of maintenance decisions for multi-unit systems. The emphasis is on three main groups of multicomponent maintenance optimization ...We present an overview of some recent developments in the area of mathematical modeling of maintenance decisions for multi-unit systems. The emphasis is on three main groups of multicomponent maintenance optimization models： the block replacement models, group maintenance models, and opportunistic maintenance models. Moreover, an example of a two-unit system maintenance process is provided in order to compare various maintenance policies.展开更多
The periodic precipitation occurs in a gel medium due to counter diffusion of ions,It is shown that the law derived earlier for double component systemcan be modified and found to be true in a multicomponent system.
Embedding a third and/or fourth component into a binary blend active layer of organic photovoltaics (OPVs) is a promising approach to achieve high-performance photovoltaic cells and modules. This multicomponent strate...Embedding a third and/or fourth component into a binary blend active layer of organic photovoltaics (OPVs) is a promising approach to achieve high-performance photovoltaic cells and modules. This multicomponent strategy favors absorption broadening via additional components. Quaternary OPV (QOPV) blends have four components in three possible configurations: (i) a donor and three acceptors, (ii) two donors and two acceptors, or (iii) three donors and an acceptor. Although quaternary systems have only been relatively recently studied compared to other systems in OPVs, leveraging the synergistic effects of the four components leads to record power conversion efficiencies, currently approaching 20%. QOPVs provide ample material choices for compatibility and channels for charge transfer mechanisms, possibly leading to optimized morphology and orientation. Reviewing recent progress in advancing QOPVs is essential for understanding their contribution to the OPV field. The review mainly discusses research progress in QOPVs with a keen interest in their various configurations, semitransparency, and outdoor and indoor applications. It describes the not-well-understood QOPV's general working mechanism. This review explores high-performance QOPVs based on the fourth component's contribution as a donor, acceptor, or dye molecule and beyond in photovoltaic applications. Finally, there is a discussion around QOPV's outlook and projected future research directions in this field. This review intends to provide an overview of the quaternary systems approach to OPVs and inform current and future researchers on investigating the full spectrum of OPVs.展开更多
Multicomponent(Hf-Zr-Ta)B_(2)potentially provides improved ablation resistance compared with silicon-based ceramics.Here we deposited(Hf_(0.5-x/2)Zr_(0.5-x/2)Ta_(x))B_(2)(x=0,0.1,and 0.2)coatings onto C/C com-posites,...Multicomponent(Hf-Zr-Ta)B_(2)potentially provides improved ablation resistance compared with silicon-based ceramics.Here we deposited(Hf_(0.5-x/2)Zr_(0.5-x/2)Ta_(x))B_(2)(x=0,0.1,and 0.2)coatings onto C/C com-posites,and investigated their ablation behaviors under an oxyacetylene torch with a heat flux of 2.4 MW m^(-2).It was observed that the x=0.1 oxide scale bulged but was denser,and the x=0.2 oxide scale was blown away due to the formation of excessive liquid.Based on these findings,we further de-veloped a duplex(Hf-Zr-Ta)B_(2)coating that showed a linear recession rate close to zero(0.11μm s^(-1))after two 120-s ablation cycles.It is identified that the resulting oxide scale is mainly composed of(Hf,Zr)_(6)Ta_(2)O_(17)and(Hf,Zr,Ta)O_(2)by performing aberration-corrected(scanning)transmission electron microscopy.The protective mechanism is related to the peritectic transformation of orthorhombic-(Hf,Zr)_(6)Ta_(2)O_(17)to tetragonal-(Hf,Zr,Ta)O_(2)plus Ta-dominated liquid.This study contributes to the develop-ment of Ta-containing multicomponent UHTC bulk and coatings for ultra-high temperature applications.展开更多
Premature adiabatic shear localization caused by strain softening is a roadblock for the application of body-centered cubic(BCC)structured high-entropy alloy(HEAs)in the impact field.A micron-scale orthorhombic-phase(...Premature adiabatic shear localization caused by strain softening is a roadblock for the application of body-centered cubic(BCC)structured high-entropy alloy(HEAs)in the impact field.A micron-scale orthorhombic-phase(O-phase)strengthened TiZrVNbAl alloy was developed to delay adiabatic shear failure and enhance dynamic ductility.The O-phase can not only reduce the slip length,but also promote the pinning and tangling of the dislocations near the phase boundaries.The introduction of the O-phase transformed the strain hardening rate from negative to positive,resulting in a significantly improved dynamic shear resistance.Meanwhile,slip transfer across the O-phase via dislocation cutting mechanisms and a reduction of slip band spacing guaranteed dynamic deformation uniformity.Benefiting from the introduction of the O-phase,the alloy exhibits an excellent stored energy density(∼446 J/cm^(3),surpass the reported BCC-HEAs and typical titanium alloys),a large dynamic fracture strain(∼42%)and a considerable dynamic specific yield strength(∼241 MPa cm^(3)g^(-1)).The present study presents an effective approach for developing BCC-HEAs with excellent dynamic shear resistance and plasticity.展开更多
Functional hyperbranched polymers,as an important class of materials,are widely applied in diverse areas.Therefore,the development of simple and efficient reactions to prepare hyperbranched polymers is of great signif...Functional hyperbranched polymers,as an important class of materials,are widely applied in diverse areas.Therefore,the development of simple and efficient reactions to prepare hyperbranched polymers is of great significance.In this work,trialdehydes,diamines,and trimethylsilyl cyanide could easily undergo multicomponent polymerization under mild conditions,producing hyperbranched poly(α-aminonitrile)s with high molecular weights(M_(w) up to 4.87×10^(4))in good yields(up to 85%).The hyperbranched poly(α-aminonitrile)s have good solubility in commonly used organic solvents,high thermal stability as well as morphological stability.Furthermore,due to the numerous aldehyde groups in their branched chains,these hb-poly(α-aminonitrile)s can undergo one-pot,two-step,four-component post-polymerization with high efficiency.This work not only confirms the efficiency of our established catalyst-free multicomponent polymerization of aldehydes,amines and trimethylsilyl cyanide,but also provides a versatile and powerful platform for the preparation of functional hyperbranched polymeric materials.展开更多
Exploration of new green polymerization strategies for the construction of conjugated polymers is important but challengeable.In this work,a multicomponent polymerization of acetylarenes,alkynones and ammonium acetate...Exploration of new green polymerization strategies for the construction of conjugated polymers is important but challengeable.In this work,a multicomponent polymerization of acetylarenes,alkynones and ammonium acetate for in situ construction of conjugated poly(triarylpyridine)s was developed.The polymerization reactions of diacetylarenes,aromatic dialkynones and NH_(4)OAc were performed in dimethylsulfoxide(DMSO)under heating in the presence of potassium tert-butoxide(t-BuOK),affording four conjugated poly(2,4,6-triarylpyridine)s(PTAPs)in satisfactory yields.The resulting PTAPs have good solubility in common organic solvents and high thermal stability with 5%weight loss temperatures reaching up to 460℃.They are also electrochemically active.The PTAPs incorporating tetraphenylethene units manifest aggregation-induced emission features.Moreover,through simply being doped into poly(vinyl alcohol)(PVA)matrix,the polymer and model compound containing triphenylamine moieties exhibit room-temperature phosphorescence properties with ultralong lifetimes up to 696.2 ms and high quantum yields up to 28.7%.This work not only provides a facile green synthetic route for conjugated polymers but also offers new insights into the design of advanced materials with unique photophysical properties.展开更多
Face-centered cubic(FCC)-structured multicomponent alloys typically exhibit good ductility but low strength.To simultaneously improve strength and ductility,a multicomponent alloy,Ni_(43.9)Co_(22.4)Fe_(8.8)Al_(10.7)Ti...Face-centered cubic(FCC)-structured multicomponent alloys typically exhibit good ductility but low strength.To simultaneously improve strength and ductility,a multicomponent alloy,Ni_(43.9)Co_(22.4)Fe_(8.8)Al_(10.7)Ti_(11.7)B_(2.5)(at%)with a unique microstructure was developed in this work.The microstructure,which includes 17.8%nanosized L12 precipitates and 26.6%micron-sized annealing twins distributed within~8μm fine FCC grains,was achieved through cryogenic rolling and subsequent annealing.The alloy exhibits a yield strength(YS)of 1063 MPa,ultimate tensile strength(UTS)of 1696 MPa,and excellent elongation of~26%.The L1_(2) precipitates and high-density grain boundaries act as a barrier to the dislocation movement,resulting in a substantial strengthening effect.In addition,the dislocations can cut through the L1_(2) precipitates that are coherent with the FCC matrix,whereas the twin boundaries can effectively absorb and store dislocations,leading to a high work-hardening rate.Furthermore,the stacking faults,Lomer-Cottrell locks,and 9-layer rhombohedral stacking sequence(9R)structures formed during tensile deformation significantly enhance strain hardening by blocking dislocation movement and accumulating dislocations,resulting in excellent comprehensive tensile properties.Theoretical calculations reveal that the grain boundaries,L1_(2)precipitates,and twin boundaries contribute the strengths of 263.8,412.6,and 68.7 MPa,respectively,accounting for 71.9%of the YS.This study introduces a promising strategy for developing multicomponent alloys with significant strength-ductility synergies.展开更多
With the evolution of nickel-based single crystal superalloys,there is an increase in heavy elements such as Re and Ru.This has made solutal convection more pronounced during the directional solidification process,lea...With the evolution of nickel-based single crystal superalloys,there is an increase in heavy elements such as Re and Ru.This has made solutal convection more pronounced during the directional solidification process,leading to solute redistribution and increasing the risk of casting defects such as low-angle grain boundaries.To avoid casting defects,downward directional solidification(DWS)method is adopted to eliminate solutal convection and change solute redistribution.However,there is currently no in-situ characterization or quantitative simulation studying the solute redistribution during DWS and upward directional solidification(UWS)processes.A multicomponent phase field simulation coupled with lattice Boltzmann method was employed to quantitatively investigate changes in dendrite morphology,solutal convection and deviation of dendrite tips from the perspective of solute redistribution during UWS and DWS processes.The simulation of microstructure agrees well with the experimental results.The mechanism that explains how solutal convection affects side branching behavior is depicted.A novel approach is introduced to characterize dendrite deviation,elucidating the reasons why defects are prone to occur under the influence of natural convection and solute redistribution.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
Background Both medication and non-medication therapies are effective approaches to control blood pressure (BP) in hypertension patients.However,the association of joint changes in antihypertensive medication use and ...Background Both medication and non-medication therapies are effective approaches to control blood pressure (BP) in hypertension patients.However,the association of joint changes in antihypertensive medication use and healthy lifestyle index (HLI)with BP control among hypertension patients is seldom reported,which needs to provide more evidence by prospective intervention studies.We examined the association of antihypertensive medication use and HLI with BP control among employees with hypertension in China based on a workplace-based multicomponent intervention program.Methods Between January 2013 and December 2014,a cluster randomized clinical trial of a workplace-based multicomponent intervention program was conducted in 60 workplaces across 20 urban areas in China.Workplaces were randomly divided into intervention (n=40) and control (n=20) groups.Basic information on employees at each workplace was collected by trained professionals,including sociodemographic characteristics,medical history,family history,lifestyle behaviors,medication status and physical measurements.After baseline,the intervention group received a 2-year intervention to achieve BP control,which included:(1) a workplace wellness program for all employees;(2) a guidelines-oriented hypertension management protocol.HLI including nonsmoking,nondrinking,adequate physical activity,weight within reference range and balanced diet,were coded on a 5-point scale (range:0-5,with higher score indicating a healthier lifestyle).Antihypertensive medication use was defined as taking drug within the last 2 weeks.Changes in HLI,antihypertensive medication use and BP control from baseline to 24 months were measured after the intervention.Results Overall,4655 employees were included (age:46.3±7.6 years,men:3547 (82.3%)).After 24 months of the intervention,there was a significant improvement in lifestyle[smoking (OR=0.65,95%CI:0.43-0.99;P=0.045),drinking (OR=0.52,95%CI:0.40-0.68;P<0.001),regular exercise (OR=3.10,95%CI:2.53-3.78;P<0.001),excessive intake of fatty food (OR=0.17,95%CI:0.06-0.52;P=0.002),restrictive use of salt (OR=0.26,95%CI:0.12-0.56;P=0.001)].Compare to employees with a deteriorating lifestyle after the intervention,those with an improved lifestyle had a higher BP control.In the intervention group,compared with employees not using antihypertensive medication,those who consistent used (OR=2.34;95%CI:1.16-4.72;P=0.017) or changed from not using to using antihypertensive medication (OR=2.24;95%CI:1.08-4.62;P=0.030) had higher BP control.Compared with those having lower HLI,participants with a same (OR=1.38;95%CI:0.99-1.93;P=0.056) or high (OR=1.79;95%CI:1.27~2.53;P<0.001) HLI had higher BP control.Those who used antihypertensive medication and had a high HLI had the highest BP control (OR=1.88;95%CI:1.32-2.67,P<0.001).Subgroup analysis also showed the consistent effect as the above.Conclusion These findings suggest that adherence to antihypertensive medication treatment and healthy lifestyle were associated with a significant improvement in BP control among employees with hypertension.展开更多
Hollow engineering plays a crucial role in enhancing interfacial polarization,which is an essential factor in microwave absorption.Herein,an in-situ growth approach was adopted to successively coating C layer and WS_(...Hollow engineering plays a crucial role in enhancing interfacial polarization,which is an essential factor in microwave absorption.Herein,an in-situ growth approach was adopted to successively coating C layer and WS_(2) nanosheets on the surface SiO_(2) nanosphere.The obtained results suggested that the formed SiO_(2)@Void@C@WS_(2) multi-component nanocomposites(MCNCs)reveal a representative flower-like yolk-shell structure,which were manufactured massively through a simple channel.Additionally,the obtained SiO_(2)@Void@C@WS_(2) MCNCs presented a more and more obvious yolk-shell structure and reduced WS_(2) content with decreasing the addition of SiO_(2)@C or tungsten and sulfur sources.Because of their distinc-tive structures and remarkable cooperative effects,the SiO_(2)@Void@C@WS_(2) displayed excellent microwave absorption performances.Through the majorization of hollow structure and WS_(2),improved properties of SiO_(2)@Void@C@WS_(2) MCNCs could be acquired owing to their boosted polarization and conductive loss capabilities.Amongst,the resulting SiO_(2)@Void@C@WS_(2) MCNCs exhibited the effective absorption band and minimum reflection loss values of 5.40 GHz and−45.50 dB with matching thicknesses of 1.78 and 1.55 mm,respectively.Therefore,our findings employed hollow engineering and optimization strategies for components to design and fabricate the yolk-shell structure flower-like MCNCs,which acted as highly efficient wide-band microwave absorbing materials.展开更多
Dimethyl sulfoxide(DMSO)possessing strong solvency and high boiling point is a very important aprotic polar solvent in organic and polymer synthesis.Notably,it is also a useful synthon in organic chemistry.However,the...Dimethyl sulfoxide(DMSO)possessing strong solvency and high boiling point is a very important aprotic polar solvent in organic and polymer synthesis.Notably,it is also a useful synthon in organic chemistry.However,the direct incorporation of DMSO in polymer synthesis remains challenging.In this work,DMSO was successfully converted to nitrogen-containing heterocyclic polymers as a monomer via multicomponent polymerizations(MCPs)with dialdehydes and diamines in the presence of K_(2)S_(2)O_(8)/t-BuOK at 120℃in 6 h.A series of poly(phenylquinoline)s with high M_(w)values(up to 5.11×10^(4))were obtained in satisfactory yields(up to 82%),performing good solubility,good thermal and morphological stability as well as excellent film-forming ability.The thin films of poly(phenylquinoline)s exhibit high refractive index value in a wide wavelength range of 400–1700 nm.Thus,this work not only enriches the family of MCPs but also provides an efficient strategy for the conversion of DMSO into functional polymeric materials that are potentially applicable in diverse areas.展开更多
Solid solutions(SS)of 3-and 4-component systems based on lead titanate-zirconate were prepared by the method of solid-phase reactions and uniaxial hot pressing.The dependences of the relative permittivity of polarized...Solid solutions(SS)of 3-and 4-component systems based on lead titanate-zirconate were prepared by the method of solid-phase reactions and uniaxial hot pressing.The dependences of the relative permittivity of polarized samples on the electronegativity(EN)of their constituent cations have been studied.The ferro-hardness of the SS(the stability of the domain structure to external influences)is shown to be directly dependent on the EN of elements B in the corresponding oxidation states,i.e.,the degree of covalence of the B-O bond.The deviation from this dependence in SS with Ni and Cd is explained by their individual features,which result in changes in the degree of bond covalence in both cationic sublattices.The conducted crystal-chemical analysis made it possible to choose promising SS when creating ferroelectric materials,including textured piezoelectric ceramic materials for piezoelectric transducers for various purposes:Piezotransformers,piezoelectric motors,ultrasonic emitters,filter devices,ultrasonic flaw detectors,accelerometers,etc.展开更多
Complex systems exist widely,including medicines from natural products,functional foods,and biological samples.The biological activity of complex systems is often the result of the synergistic effect of multiple compo...Complex systems exist widely,including medicines from natural products,functional foods,and biological samples.The biological activity of complex systems is often the result of the synergistic effect of multiple components.In the quality evaluation of complex samples,multicomponent quantitative analysis(MCQA)is usually needed.To overcome the difficulty in obtaining standard products,scholars have proposed achieving MCQA through the“single standard to determine multiple components(SSDMC)”approach.This method has been used in the determination of multicomponent content in natural source drugs and the analysis of impurities in chemical drugs and has been included in the Chinese Pharmacopoeia.Depending on a convenient(ultra)high-performance liquid chromatography method,how can the repeatability and robustness of the MCQA method be improved?How can the chromatography conditions be optimized to improve the number of quantitative components?How can computer software technology be introduced to improve the efficiency of multicomponent analysis(MCA)?These are the key problems that remain to be solved in practical MCQA.First,this review article summarizes the calculation methods of relative correction factors in the SSDMC approach in the past five years,as well as the method robustness and accuracy evaluation.Second,it also summarizes methods to improve peak capacity and quantitative accuracy in MCA,including column selection and twodimensional chromatographic analysis technology.Finally,computer software technologies for predicting chromatographic conditions and analytical parameters are introduced,which provides an idea for intelligent method development in MCA.This paper aims to provide methodological ideas for the improvement of complex system analysis,especially MCQA.展开更多
Perovskite-type rare-earth ferrites(REFeO_(3))are promising materials for absorbing electromagnetic(EM)wave pollution.However,insufficient dielectric loss and poor impedance matching are key factors that limit the bro...Perovskite-type rare-earth ferrites(REFeO_(3))are promising materials for absorbing electromagnetic(EM)wave pollution.However,insufficient dielectric loss and poor impedance matching are key factors that limit the broader implementation of REFeO_(3).Herein,a series of multicomponent perovskite-type ferrites with strong EM wave absorption capabilities was prepared.Through the synergistic effect of chemical constitution regulation and entropy regulation,optimization of the dielectric loss and impedance matching is achieved by strengthening the structural defect mechanism,thus further adjusting the EM wave absorption performance.Compared with(LaGdSmNdBa)FeO_(3)(HE-1)and(LaGdPrSmNdBa)FeO_(3)(HE-2),(LaGdBa)FeO_(3)(ME-1)and(LaGdSmBa)FeO_(3)(ME-2)exhibit favorable performance,with optimal minimum reflection loss(RL_(min))of-56.35 dB(at 11.12 GHz)and-63.25 dB(at 7.22 GHz)and effective absorption bandwidth(EAB)of 4.46 and 4.72 GHz,respectively.This multicomponent design provides a new strategy for the development of EM wave absorption materials.展开更多
The rapid development of electric vehicles and portable energy storage systems demands improvements in the energy density and cost-effectiveness of lithium-ion batteries,a domain in which Lithium-rich layered cathode(...The rapid development of electric vehicles and portable energy storage systems demands improvements in the energy density and cost-effectiveness of lithium-ion batteries,a domain in which Lithium-rich layered cathode(LLO)materials inherently excel.However,these materials face practical challenges,such as low initial Coulombic efficiency,inferior cycle/rate performance,and voltage decline during cycling,which limit practical application.Our study introduces a surface multi-component integration strategy that incorporates oxygen vacancies into the pristine LLO material Li1.2Mn_(0.6)Ni_(0.2)O_(2).This process involves a brief citric acid treatment followed by calcination,aiming to explore rate-dependent degradation behavior.The induced surface oxygen vacancies can reduce surface oxygen partial pressure and diminish the generation of O_(2)and other highly reactive oxygen species on the surface,thereby facilitating the activation of Li ions trapped in tetrahedral sites while overcoming transport barriers.Additionally,the formation of a spinel-like phase with 3D Li+diffusion channels significantly improves Li^(+)diffusion kinetics and stabilizes the surface structure.The optimally modified sample boasts a discharge capacity of 299.5 mA h g^(-1)at a 0.1 C and 251.6 mA h g^(-1)at a 1 C during the initial activation cycle,with an impressive capacity of 222.1 mA h g^(-1)at a 5 C.Most notably,it retained nearly 70%of its capacity after 300 cycles at this elevated rate.This straightforward,effective,and highly viable modification strategy provides a crucial resolution for overcoming challenges associated with LLO materials,making them more suitable for practical application.展开更多
Three adsorption rate rnodels are derived for multicomponent adsorption systems under either pore diffusion or surface diffusion control. The linear driving force (LDF) model is obtained by assuming a parabolic intrap...Three adsorption rate rnodels are derived for multicomponent adsorption systems under either pore diffusion or surface diffusion control. The linear driving force (LDF) model is obtained by assuming a parabolic intraparticle concentration profile. Models Ⅰ and Ⅱ are obtained from the parabolic concentration layer approximation. Examples are presented to demonstrate the usage and accuracy of these models. It is shown that Model Ⅰ is suitable for batch adsorption calculations and Model Ⅱ provides a good approximation in fixed-bed adsorption pro-cesses while the LDF model should not be used in batch adsorption and may be considered acceptable in fixed-bed adsorption where the parameter Ti is relatively large.展开更多
This paper presents a set of multicomponent matrix Lie algebra, which is used to construct a new loop algebra A^-M. By using the Tu scheme, a Liouville integrable multicomponent equation hierarchy is generated, which ...This paper presents a set of multicomponent matrix Lie algebra, which is used to construct a new loop algebra A^-M. By using the Tu scheme, a Liouville integrable multicomponent equation hierarchy is generated, which possesses the Hamiltonian structure. As its reduction cases, the multicomponent （2＋1）-dimensional Glachette-Johnson （G J） hierarchy is given. Finally, the super-integrable coupling system of multicomponent （2＋1）-dimensional GJ hierarchy is established through enlarging the spectral problem.展开更多
Multiphase design is a promising approach to achieve superior ablation resistance of multicomponent ultra-high temperature ceramic,while understanding the ablation mechanism is the foundation.Here,through investigatin...Multiphase design is a promising approach to achieve superior ablation resistance of multicomponent ultra-high temperature ceramic,while understanding the ablation mechanism is the foundation.Here,through investigating a three-phase multicomponent ceramic consisting of Hf-rich carbide,Nb-rich carbide,and Zr-rich silicide phases,we report a newly discovered solid-state reaction process among multiphase multicomponent ceramic during ablation.It was found that this solid-state reaction occurred in the matrix/oxide scale interface region.In this process,metal cations are counter-diffused between the multicomponent phases,thereby resulting in their composition evolution,which allows the multicomponent phases to exist stably under a higher oxygen partial pressure,leading to the improvement of thermodynamic stability of three-phase multicomponent ceramic.Additionally,this solid-state reaction process appears synergistic with the preferential oxidation behavior among the oxide scale in enhancing the ablation performance.展开更多
文摘We present an overview of some recent developments in the area of mathematical modeling of maintenance decisions for multi-unit systems. The emphasis is on three main groups of multicomponent maintenance optimization models： the block replacement models, group maintenance models, and opportunistic maintenance models. Moreover, an example of a two-unit system maintenance process is provided in order to compare various maintenance policies.
文摘The periodic precipitation occurs in a gel medium due to counter diffusion of ions,It is shown that the law derived earlier for double component systemcan be modified and found to be true in a multicomponent system.
基金the support of the research commission of the Catholic University of Lille and its Foundationthe IEMN laboratory for the financial supportsupport from the Materials Research Institute (MRI) and the Institute of Energy and the Environment (IEE) of the Pennsylvania State University。
文摘Embedding a third and/or fourth component into a binary blend active layer of organic photovoltaics (OPVs) is a promising approach to achieve high-performance photovoltaic cells and modules. This multicomponent strategy favors absorption broadening via additional components. Quaternary OPV (QOPV) blends have four components in three possible configurations: (i) a donor and three acceptors, (ii) two donors and two acceptors, or (iii) three donors and an acceptor. Although quaternary systems have only been relatively recently studied compared to other systems in OPVs, leveraging the synergistic effects of the four components leads to record power conversion efficiencies, currently approaching 20%. QOPVs provide ample material choices for compatibility and channels for charge transfer mechanisms, possibly leading to optimized morphology and orientation. Reviewing recent progress in advancing QOPVs is essential for understanding their contribution to the OPV field. The review mainly discusses research progress in QOPVs with a keen interest in their various configurations, semitransparency, and outdoor and indoor applications. It describes the not-well-understood QOPV's general working mechanism. This review explores high-performance QOPVs based on the fourth component's contribution as a donor, acceptor, or dye molecule and beyond in photovoltaic applications. Finally, there is a discussion around QOPV's outlook and projected future research directions in this field. This review intends to provide an overview of the quaternary systems approach to OPVs and inform current and future researchers on investigating the full spectrum of OPVs.
基金supported by the National Key R&D Pro-gram of China(Grant No.2021YFA0715803)the National Natural Science Foundation of China(Grant Nos.52293373,52130205,and 52302091)+1 种基金the Joint Fund of Henan Province Science and Technol-ogy R&D Program(No.225200810002)the ND Basic Research Funds of Northwestern Polytechnical University(No.G2022WD).
文摘Multicomponent(Hf-Zr-Ta)B_(2)potentially provides improved ablation resistance compared with silicon-based ceramics.Here we deposited(Hf_(0.5-x/2)Zr_(0.5-x/2)Ta_(x))B_(2)(x=0,0.1,and 0.2)coatings onto C/C com-posites,and investigated their ablation behaviors under an oxyacetylene torch with a heat flux of 2.4 MW m^(-2).It was observed that the x=0.1 oxide scale bulged but was denser,and the x=0.2 oxide scale was blown away due to the formation of excessive liquid.Based on these findings,we further de-veloped a duplex(Hf-Zr-Ta)B_(2)coating that showed a linear recession rate close to zero(0.11μm s^(-1))after two 120-s ablation cycles.It is identified that the resulting oxide scale is mainly composed of(Hf,Zr)_(6)Ta_(2)O_(17)and(Hf,Zr,Ta)O_(2)by performing aberration-corrected(scanning)transmission electron microscopy.The protective mechanism is related to the peritectic transformation of orthorhombic-(Hf,Zr)_(6)Ta_(2)O_(17)to tetragonal-(Hf,Zr,Ta)O_(2)plus Ta-dominated liquid.This study contributes to the develop-ment of Ta-containing multicomponent UHTC bulk and coatings for ultra-high temperature applications.
基金supported by the YEQISUN Joint Funds of the National Natural Science Foundation of China(Grant No.U2241234)the National Natural Science Foundation of China(Grant No.52301127).
文摘Premature adiabatic shear localization caused by strain softening is a roadblock for the application of body-centered cubic(BCC)structured high-entropy alloy(HEAs)in the impact field.A micron-scale orthorhombic-phase(O-phase)strengthened TiZrVNbAl alloy was developed to delay adiabatic shear failure and enhance dynamic ductility.The O-phase can not only reduce the slip length,but also promote the pinning and tangling of the dislocations near the phase boundaries.The introduction of the O-phase transformed the strain hardening rate from negative to positive,resulting in a significantly improved dynamic shear resistance.Meanwhile,slip transfer across the O-phase via dislocation cutting mechanisms and a reduction of slip band spacing guaranteed dynamic deformation uniformity.Benefiting from the introduction of the O-phase,the alloy exhibits an excellent stored energy density(∼446 J/cm^(3),surpass the reported BCC-HEAs and typical titanium alloys),a large dynamic fracture strain(∼42%)and a considerable dynamic specific yield strength(∼241 MPa cm^(3)g^(-1)).The present study presents an effective approach for developing BCC-HEAs with excellent dynamic shear resistance and plasticity.
基金financially supported by the Scientific Research Start-up Fund Project of Anhui Polytechnic University for Introducing Talents(No.2022YQQ081)Natural Science Research Project of Anhui Educational Committee(No.2024AH050133)the National Natural Science Foundation of China(No.22001078).
文摘Functional hyperbranched polymers,as an important class of materials,are widely applied in diverse areas.Therefore,the development of simple and efficient reactions to prepare hyperbranched polymers is of great significance.In this work,trialdehydes,diamines,and trimethylsilyl cyanide could easily undergo multicomponent polymerization under mild conditions,producing hyperbranched poly(α-aminonitrile)s with high molecular weights(M_(w) up to 4.87×10^(4))in good yields(up to 85%).The hyperbranched poly(α-aminonitrile)s have good solubility in commonly used organic solvents,high thermal stability as well as morphological stability.Furthermore,due to the numerous aldehyde groups in their branched chains,these hb-poly(α-aminonitrile)s can undergo one-pot,two-step,four-component post-polymerization with high efficiency.This work not only confirms the efficiency of our established catalyst-free multicomponent polymerization of aldehydes,amines and trimethylsilyl cyanide,but also provides a versatile and powerful platform for the preparation of functional hyperbranched polymeric materials.
基金supported by the National Natural Science Foundation of China(No.22071166)the Priority Academic Program Development of Jiangsu High Education Institutions(PAPD).
文摘Exploration of new green polymerization strategies for the construction of conjugated polymers is important but challengeable.In this work,a multicomponent polymerization of acetylarenes,alkynones and ammonium acetate for in situ construction of conjugated poly(triarylpyridine)s was developed.The polymerization reactions of diacetylarenes,aromatic dialkynones and NH_(4)OAc were performed in dimethylsulfoxide(DMSO)under heating in the presence of potassium tert-butoxide(t-BuOK),affording four conjugated poly(2,4,6-triarylpyridine)s(PTAPs)in satisfactory yields.The resulting PTAPs have good solubility in common organic solvents and high thermal stability with 5%weight loss temperatures reaching up to 460℃.They are also electrochemically active.The PTAPs incorporating tetraphenylethene units manifest aggregation-induced emission features.Moreover,through simply being doped into poly(vinyl alcohol)(PVA)matrix,the polymer and model compound containing triphenylamine moieties exhibit room-temperature phosphorescence properties with ultralong lifetimes up to 696.2 ms and high quantum yields up to 28.7%.This work not only provides a facile green synthetic route for conjugated polymers but also offers new insights into the design of advanced materials with unique photophysical properties.
基金supported by the Major Science and Technology Project of Gansu Province(Nos.23ZDGA010 and 22ZD6GA008)the National Natural Science Foundation of China(No.51564035).
文摘Face-centered cubic(FCC)-structured multicomponent alloys typically exhibit good ductility but low strength.To simultaneously improve strength and ductility,a multicomponent alloy,Ni_(43.9)Co_(22.4)Fe_(8.8)Al_(10.7)Ti_(11.7)B_(2.5)(at%)with a unique microstructure was developed in this work.The microstructure,which includes 17.8%nanosized L12 precipitates and 26.6%micron-sized annealing twins distributed within~8μm fine FCC grains,was achieved through cryogenic rolling and subsequent annealing.The alloy exhibits a yield strength(YS)of 1063 MPa,ultimate tensile strength(UTS)of 1696 MPa,and excellent elongation of~26%.The L1_(2) precipitates and high-density grain boundaries act as a barrier to the dislocation movement,resulting in a substantial strengthening effect.In addition,the dislocations can cut through the L1_(2) precipitates that are coherent with the FCC matrix,whereas the twin boundaries can effectively absorb and store dislocations,leading to a high work-hardening rate.Furthermore,the stacking faults,Lomer-Cottrell locks,and 9-layer rhombohedral stacking sequence(9R)structures formed during tensile deformation significantly enhance strain hardening by blocking dislocation movement and accumulating dislocations,resulting in excellent comprehensive tensile properties.Theoretical calculations reveal that the grain boundaries,L1_(2)precipitates,and twin boundaries contribute the strengths of 263.8,412.6,and 68.7 MPa,respectively,accounting for 71.9%of the YS.This study introduces a promising strategy for developing multicomponent alloys with significant strength-ductility synergies.
基金supported by the stable support project and the Major National Science and Technology Project(2017-VII-0008-0101).
文摘With the evolution of nickel-based single crystal superalloys,there is an increase in heavy elements such as Re and Ru.This has made solutal convection more pronounced during the directional solidification process,leading to solute redistribution and increasing the risk of casting defects such as low-angle grain boundaries.To avoid casting defects,downward directional solidification(DWS)method is adopted to eliminate solutal convection and change solute redistribution.However,there is currently no in-situ characterization or quantitative simulation studying the solute redistribution during DWS and upward directional solidification(UWS)processes.A multicomponent phase field simulation coupled with lattice Boltzmann method was employed to quantitatively investigate changes in dendrite morphology,solutal convection and deviation of dendrite tips from the perspective of solute redistribution during UWS and DWS processes.The simulation of microstructure agrees well with the experimental results.The mechanism that explains how solutal convection affects side branching behavior is depicted.A novel approach is introduced to characterize dendrite deviation,elucidating the reasons why defects are prone to occur under the influence of natural convection and solute redistribution.
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supported by grant 2011BAI11B01 from the Projects in the Chinese National Science and Technology Pillar Program during the 12th Five-year Plan Periodby grant 2017-I2M-1-004 from the Chinese Academy of Medical Science Innovation Fund for Medical Sciencesby the Major science and technology special plan project of Yunnan Province (202302AA310045)。
文摘Background Both medication and non-medication therapies are effective approaches to control blood pressure (BP) in hypertension patients.However,the association of joint changes in antihypertensive medication use and healthy lifestyle index (HLI)with BP control among hypertension patients is seldom reported,which needs to provide more evidence by prospective intervention studies.We examined the association of antihypertensive medication use and HLI with BP control among employees with hypertension in China based on a workplace-based multicomponent intervention program.Methods Between January 2013 and December 2014,a cluster randomized clinical trial of a workplace-based multicomponent intervention program was conducted in 60 workplaces across 20 urban areas in China.Workplaces were randomly divided into intervention (n=40) and control (n=20) groups.Basic information on employees at each workplace was collected by trained professionals,including sociodemographic characteristics,medical history,family history,lifestyle behaviors,medication status and physical measurements.After baseline,the intervention group received a 2-year intervention to achieve BP control,which included:(1) a workplace wellness program for all employees;(2) a guidelines-oriented hypertension management protocol.HLI including nonsmoking,nondrinking,adequate physical activity,weight within reference range and balanced diet,were coded on a 5-point scale (range:0-5,with higher score indicating a healthier lifestyle).Antihypertensive medication use was defined as taking drug within the last 2 weeks.Changes in HLI,antihypertensive medication use and BP control from baseline to 24 months were measured after the intervention.Results Overall,4655 employees were included (age:46.3±7.6 years,men:3547 (82.3%)).After 24 months of the intervention,there was a significant improvement in lifestyle[smoking (OR=0.65,95%CI:0.43-0.99;P=0.045),drinking (OR=0.52,95%CI:0.40-0.68;P<0.001),regular exercise (OR=3.10,95%CI:2.53-3.78;P<0.001),excessive intake of fatty food (OR=0.17,95%CI:0.06-0.52;P=0.002),restrictive use of salt (OR=0.26,95%CI:0.12-0.56;P=0.001)].Compare to employees with a deteriorating lifestyle after the intervention,those with an improved lifestyle had a higher BP control.In the intervention group,compared with employees not using antihypertensive medication,those who consistent used (OR=2.34;95%CI:1.16-4.72;P=0.017) or changed from not using to using antihypertensive medication (OR=2.24;95%CI:1.08-4.62;P=0.030) had higher BP control.Compared with those having lower HLI,participants with a same (OR=1.38;95%CI:0.99-1.93;P=0.056) or high (OR=1.79;95%CI:1.27~2.53;P<0.001) HLI had higher BP control.Those who used antihypertensive medication and had a high HLI had the highest BP control (OR=1.88;95%CI:1.32-2.67,P<0.001).Subgroup analysis also showed the consistent effect as the above.Conclusion These findings suggest that adherence to antihypertensive medication treatment and healthy lifestyle were associated with a significant improvement in BP control among employees with hypertension.
基金supported by the Guizhou Provincial Science and Technology Projects for Platform and Talent Team Plan(No.GCC[2023]007)the Innovation Group of Guizhou University([2024]08)+1 种基金Fok Ying Tung Education Foundation(No.171095)the National Natural Science Foundation of China(No.11964006).
文摘Hollow engineering plays a crucial role in enhancing interfacial polarization,which is an essential factor in microwave absorption.Herein,an in-situ growth approach was adopted to successively coating C layer and WS_(2) nanosheets on the surface SiO_(2) nanosphere.The obtained results suggested that the formed SiO_(2)@Void@C@WS_(2) multi-component nanocomposites(MCNCs)reveal a representative flower-like yolk-shell structure,which were manufactured massively through a simple channel.Additionally,the obtained SiO_(2)@Void@C@WS_(2) MCNCs presented a more and more obvious yolk-shell structure and reduced WS_(2) content with decreasing the addition of SiO_(2)@C or tungsten and sulfur sources.Because of their distinc-tive structures and remarkable cooperative effects,the SiO_(2)@Void@C@WS_(2) displayed excellent microwave absorption performances.Through the majorization of hollow structure and WS_(2),improved properties of SiO_(2)@Void@C@WS_(2) MCNCs could be acquired owing to their boosted polarization and conductive loss capabilities.Amongst,the resulting SiO_(2)@Void@C@WS_(2) MCNCs exhibited the effective absorption band and minimum reflection loss values of 5.40 GHz and−45.50 dB with matching thicknesses of 1.78 and 1.55 mm,respectively.Therefore,our findings employed hollow engineering and optimization strategies for components to design and fabricate the yolk-shell structure flower-like MCNCs,which acted as highly efficient wide-band microwave absorbing materials.
基金supported by the Scientific Research Start-up Fund Project of Anhui Polytechnic University for Introducing Talents(No.2022YQQ081)Natural Science Research Project of the Anhui Educational Committee(No.2024AH050133)the National Natural Science Foundation of China(No.22101088)。
文摘Dimethyl sulfoxide(DMSO)possessing strong solvency and high boiling point is a very important aprotic polar solvent in organic and polymer synthesis.Notably,it is also a useful synthon in organic chemistry.However,the direct incorporation of DMSO in polymer synthesis remains challenging.In this work,DMSO was successfully converted to nitrogen-containing heterocyclic polymers as a monomer via multicomponent polymerizations(MCPs)with dialdehydes and diamines in the presence of K_(2)S_(2)O_(8)/t-BuOK at 120℃in 6 h.A series of poly(phenylquinoline)s with high M_(w)values(up to 5.11×10^(4))were obtained in satisfactory yields(up to 82%),performing good solubility,good thermal and morphological stability as well as excellent film-forming ability.The thin films of poly(phenylquinoline)s exhibit high refractive index value in a wide wavelength range of 400–1700 nm.Thus,this work not only enriches the family of MCPs but also provides an efficient strategy for the conversion of DMSO into functional polymeric materials that are potentially applicable in diverse areas.
基金This study was financially supported by the Ministry of Science and Higher Education of the Russian Federation(State task in the field of scientific activity,scientific project No.(0852-2020-0032)/(BAZ0110/20-3-07IF))This report is presented at the 10th Anniversary International Conference on“Physics and Mechanics of New Materials and Their Applications”(PHENMA 2021),Divnomorsk,Russia,May 23-27,2022.
文摘Solid solutions(SS)of 3-and 4-component systems based on lead titanate-zirconate were prepared by the method of solid-phase reactions and uniaxial hot pressing.The dependences of the relative permittivity of polarized samples on the electronegativity(EN)of their constituent cations have been studied.The ferro-hardness of the SS(the stability of the domain structure to external influences)is shown to be directly dependent on the EN of elements B in the corresponding oxidation states,i.e.,the degree of covalence of the B-O bond.The deviation from this dependence in SS with Ni and Cd is explained by their individual features,which result in changes in the degree of bond covalence in both cationic sublattices.The conducted crystal-chemical analysis made it possible to choose promising SS when creating ferroelectric materials,including textured piezoelectric ceramic materials for piezoelectric transducers for various purposes:Piezotransformers,piezoelectric motors,ultrasonic emitters,filter devices,ultrasonic flaw detectors,accelerometers,etc.
基金the National Natural Science Foundation of China(Grant No.:81803734)National S&T Major Special Project for New Innovative Drugs Sponsored(Grant No.:2019ZX09201005).
文摘Complex systems exist widely,including medicines from natural products,functional foods,and biological samples.The biological activity of complex systems is often the result of the synergistic effect of multiple components.In the quality evaluation of complex samples,multicomponent quantitative analysis(MCQA)is usually needed.To overcome the difficulty in obtaining standard products,scholars have proposed achieving MCQA through the“single standard to determine multiple components(SSDMC)”approach.This method has been used in the determination of multicomponent content in natural source drugs and the analysis of impurities in chemical drugs and has been included in the Chinese Pharmacopoeia.Depending on a convenient(ultra)high-performance liquid chromatography method,how can the repeatability and robustness of the MCQA method be improved?How can the chromatography conditions be optimized to improve the number of quantitative components?How can computer software technology be introduced to improve the efficiency of multicomponent analysis(MCA)?These are the key problems that remain to be solved in practical MCQA.First,this review article summarizes the calculation methods of relative correction factors in the SSDMC approach in the past five years,as well as the method robustness and accuracy evaluation.Second,it also summarizes methods to improve peak capacity and quantitative accuracy in MCA,including column selection and twodimensional chromatographic analysis technology.Finally,computer software technologies for predicting chromatographic conditions and analytical parameters are introduced,which provides an idea for intelligent method development in MCA.This paper aims to provide methodological ideas for the improvement of complex system analysis,especially MCQA.
基金Project supported by the National Key Research and Development Program of China(2022YFB3504302)the Young Elite Scientists Sponsorship Program by CAST(YESS20210336)+1 种基金the Fujian Provincial Natural Fund Project(2021J05101)the XIREM Autonomously Deployment Project(2023GG03)。
文摘Perovskite-type rare-earth ferrites(REFeO_(3))are promising materials for absorbing electromagnetic(EM)wave pollution.However,insufficient dielectric loss and poor impedance matching are key factors that limit the broader implementation of REFeO_(3).Herein,a series of multicomponent perovskite-type ferrites with strong EM wave absorption capabilities was prepared.Through the synergistic effect of chemical constitution regulation and entropy regulation,optimization of the dielectric loss and impedance matching is achieved by strengthening the structural defect mechanism,thus further adjusting the EM wave absorption performance.Compared with(LaGdSmNdBa)FeO_(3)(HE-1)and(LaGdPrSmNdBa)FeO_(3)(HE-2),(LaGdBa)FeO_(3)(ME-1)and(LaGdSmBa)FeO_(3)(ME-2)exhibit favorable performance,with optimal minimum reflection loss(RL_(min))of-56.35 dB(at 11.12 GHz)and-63.25 dB(at 7.22 GHz)and effective absorption bandwidth(EAB)of 4.46 and 4.72 GHz,respectively.This multicomponent design provides a new strategy for the development of EM wave absorption materials.
基金supported by the National Key R&D Program of China(2021YFB2401800)the National Natural Science Foundation of China(21875022,22179008)+4 种基金the Yibin‘Jie Bang Gua Shuai’(2022JB004)the support from the Beijing Nova Program(20230484241)the support from the Postdoctoral Fellowship Program of CPSF(GZB20230931)the support from the 4B7B beam line of Beijing Synchrotron Radiation Facility(2021-BEPC-PT-005924,2021-BEPC-PT-005967)BL08U1A beam line of Shanghai Synchrotron Radiation Facility(2021-SSRF-PT-017710)。
文摘The rapid development of electric vehicles and portable energy storage systems demands improvements in the energy density and cost-effectiveness of lithium-ion batteries,a domain in which Lithium-rich layered cathode(LLO)materials inherently excel.However,these materials face practical challenges,such as low initial Coulombic efficiency,inferior cycle/rate performance,and voltage decline during cycling,which limit practical application.Our study introduces a surface multi-component integration strategy that incorporates oxygen vacancies into the pristine LLO material Li1.2Mn_(0.6)Ni_(0.2)O_(2).This process involves a brief citric acid treatment followed by calcination,aiming to explore rate-dependent degradation behavior.The induced surface oxygen vacancies can reduce surface oxygen partial pressure and diminish the generation of O_(2)and other highly reactive oxygen species on the surface,thereby facilitating the activation of Li ions trapped in tetrahedral sites while overcoming transport barriers.Additionally,the formation of a spinel-like phase with 3D Li+diffusion channels significantly improves Li^(+)diffusion kinetics and stabilizes the surface structure.The optimally modified sample boasts a discharge capacity of 299.5 mA h g^(-1)at a 0.1 C and 251.6 mA h g^(-1)at a 1 C during the initial activation cycle,with an impressive capacity of 222.1 mA h g^(-1)at a 5 C.Most notably,it retained nearly 70%of its capacity after 300 cycles at this elevated rate.This straightforward,effective,and highly viable modification strategy provides a crucial resolution for overcoming challenges associated with LLO materials,making them more suitable for practical application.
基金Supported by the National Natural Science Foundation of China (No. 30070636).
文摘Three adsorption rate rnodels are derived for multicomponent adsorption systems under either pore diffusion or surface diffusion control. The linear driving force (LDF) model is obtained by assuming a parabolic intraparticle concentration profile. Models Ⅰ and Ⅱ are obtained from the parabolic concentration layer approximation. Examples are presented to demonstrate the usage and accuracy of these models. It is shown that Model Ⅰ is suitable for batch adsorption calculations and Model Ⅱ provides a good approximation in fixed-bed adsorption pro-cesses while the LDF model should not be used in batch adsorption and may be considered acceptable in fixed-bed adsorption where the parameter Ti is relatively large.
基金supported by the National Key Basic Research Development of China (Grant No 2004CB318000)
文摘This paper presents a set of multicomponent matrix Lie algebra, which is used to construct a new loop algebra A^-M. By using the Tu scheme, a Liouville integrable multicomponent equation hierarchy is generated, which possesses the Hamiltonian structure. As its reduction cases, the multicomponent （2＋1）-dimensional Glachette-Johnson （G J） hierarchy is given. Finally, the super-integrable coupling system of multicomponent （2＋1）-dimensional GJ hierarchy is established through enlarging the spectral problem.
基金supported by the National Natural Science Foundation of China(52072410 and 51602349).
文摘Multiphase design is a promising approach to achieve superior ablation resistance of multicomponent ultra-high temperature ceramic,while understanding the ablation mechanism is the foundation.Here,through investigating a three-phase multicomponent ceramic consisting of Hf-rich carbide,Nb-rich carbide,and Zr-rich silicide phases,we report a newly discovered solid-state reaction process among multiphase multicomponent ceramic during ablation.It was found that this solid-state reaction occurred in the matrix/oxide scale interface region.In this process,metal cations are counter-diffused between the multicomponent phases,thereby resulting in their composition evolution,which allows the multicomponent phases to exist stably under a higher oxygen partial pressure,leading to the improvement of thermodynamic stability of three-phase multicomponent ceramic.Additionally,this solid-state reaction process appears synergistic with the preferential oxidation behavior among the oxide scale in enhancing the ablation performance.
