The Cretaceous gold deposits along the margins of the North China Craton(NCC),which formed in a craton destruction setting,display geological characteristics similar to traditional orogenic gold deposits typically ass...The Cretaceous gold deposits along the margins of the North China Craton(NCC),which formed in a craton destruction setting,display geological characteristics similar to traditional orogenic gold deposits typically associated with accretionary orogeny.These deposits,known as Jiaodong-type gold deposits,have attracted considerable attention.However,the lithospheric controls and formation mechanisms of these deposits remain unclear,as they cannot be fully explained by the supracrustal metamorphic genetic model commonly applied to classic orogenic gold deposits.In this study,the compiled S-Hg-Pb isotope ratios of gold deposits on different NCC margins display compatible variations to the Sr-Nd-Hg isotope ratios of mafic dikes spatial-temporally associated with the deposits.This implies that mantle lithosphere,metasomatized by variable proportions of oceanic and continental crust,was the source for both gold deposits and mafic dikes.Increase of oxygen fugacity and zirconεHf(t)from pre-to syn-gold granites suggests continuous basic magma underplating,which could induce concentrations of Au-rich sulfides and contribute additional Au to auriferous CO_(2)-rich fluids derived from metasomatized mantle lithosphere and basic magma.Localization of gold deposits was controlled by craton-margin sinistral shearing induced by clockwise rotation of the craton coincident with distal emplacement of metamorphic core complexes.Thus,the Cretaceous Jiaodong-type orogenic gold deposits were derived from fertilized mantle lithosphere through such crust-mantle processes within a lithosphere thinning background.展开更多
Regolith,widely distributed on the Earth’s surface,constitutes a significant compartment of the Critical Zone,resulting from intricate interactions among the atmosphere,lithosphere,hydrosphere,and biosphere.Regolith ...Regolith,widely distributed on the Earth’s surface,constitutes a significant compartment of the Critical Zone,resulting from intricate interactions among the atmosphere,lithosphere,hydrosphere,and biosphere.Regolith formation critically influences nutrient release,soil production,and long-term climate regulation.Regolith development is governed by two primary processes:production and denudation.An urgent need exists to comprehensively understand these processes to refine our understanding of Critical Zone functions.This study investigates an in-situ regolith profile developed on granitic bedrock from a tropical region(Sanya,China).We conducted geochemical analyses,encompassing major,trace elements and mineralogical compositions as well as U-series isotopes,and applied the U-series disequilibrium method to investigate the formation history of this profile.Alternatively,dividing the regolith profile into sub-weathering zones provides a better explanation for the geochemical results,and a multi-stage model based on this subdivision effectively interprets the evolution of deep regolith.Utilizing this multi-stage model,regolith production rates is derived from the“gain and loss”model,ranging from 1.27±0.03 to 42.42±24.24 m/Ma.The production rates first increase from surface until a maximum rate is reached at the depth of∼160 cm and then decrease at further deeper horizons along the depth profile,and the variation of production rates follows a so-called“humped function”.This pioneering investigation into regolith production rates in the Chinese tropical region indicates that(1)the studied profile deviates from a steady state compared to the denudation rate derived from cosmogenic nuclides(^(10)Be_in-situ);(2)subdividing the deep profile based on geochemical data and U-series isotopic activity ratios is imperative for accurately determining regolith production rates;and(3)the combination of U-series disequilibrium and cosmogenic nuclides robustly evaluates the quantitative evolution state of regolith over long time scales.展开更多
Investing in disaster risk reduction is crucial for minimizing the impacts of disasters.However,little is known about the factors that influence changes in investment levels over time.This study aims to identify the k...Investing in disaster risk reduction is crucial for minimizing the impacts of disasters.However,little is known about the factors that influence changes in investment levels over time.This study aims to identify the key socio-economic drivers behind increases and decreases in flood protection investment in People’s Republic of China(PRC).Such information is crucial for policy makers to justify flood investments.By analyzing data on flood protection expenditures,economic losses from floods,and other relevant indicators from 1980 to 2020,the study evaluates the relationship between investment and disaster impacts through the lens of the flood investment cycle model.It was found that the country succeeded in reducing flood damage because of increasing investment in flood protection.The results indicate that changes in PRC’s flood protection investment have been driven by three major factors:the occurrence of major disasters,the fiscal situation,and shifts in government policies.Investment tended to increase following large-scale events,such as the 1998 Yangtze River Basin flood and the 2008 Wenchuan earthquake,which prompted policy changes and renewed focus on DRR measures.Fiscal constraints limited investment in the 1990s,but reforms and stimulus measures improved the financial situation,enabling increased spending on flood protection.PRC’s experience in steadily reducing flood damage through sustained investment and policy commitment offers valuable lessons for other developing countries facing similar challenges.展开更多
There is a need and opportunity for China to develop education and practice innovations given that advance practice nurses (APNs) improve health care and outcomes.The China Medical Board (CMB)China Nursing Network (CC...There is a need and opportunity for China to develop education and practice innovations given that advance practice nurses (APNs) improve health care and outcomes.The China Medical Board (CMB)China Nursing Network (CCNN) began planning for an Advanced Nursing Practice Program for education and career development that will facilitate CCNN's contributions to meeting national nursing policy priorities.This paper presents the discussion,recommendations and action plans developed at the inaugural planning meeting on June 26,2015 at Fudan University in Shanghai.The recommendations are:Develop standards for advanced nursing practice;Develop Master's level curricula based on the standards;Commence pilot projects across a number of University affiliated hospitals;and Prepare clinical tutors and faculty.The strategic directions and actions are: Develop a clinical career ladder system;Expand the nursing role from hospital to community;and Build a specialty nurse accreditation system.展开更多
Major, trace and rare earth element （REE） concentrations of Late Triassic sediments （fine- grained sandstones and mudstones） from Hongcan Well 1 in the NE part of the Songpan-Ganzi Basin, western China, are used t...Major, trace and rare earth element （REE） concentrations of Late Triassic sediments （fine- grained sandstones and mudstones） from Hongcan Well 1 in the NE part of the Songpan-Ganzi Basin, western China, are used to reveal weathering, provenance and tectonic setting of inferred source areas. The Chemical Index of Alteration （CIA） reflects a low to moderate degree of chemical weathering in a cool and somewhat dry climate, and an A-CN-K plot suggests an older upper continental crust prove- nance dominated by felsic to intermediate igneous rocks of average tonalite composition. Based on the various geochemical tectonic setting discrimination diagrams, the Late Triassic sediments are inferred to have been deposited in a back-arc basin situated between an active continental margin （the Kunlun- Qinling Fold Belt） and a continental island arc （the Yidun Island Arc）. The Triassic sediments in the study area underwent a rapid erosion and burial in a proximal slope-basin environment by the petrographic data,while the published flow directions of Triassic turbidites in the Aba-Zoige region was not supported Yidun volcanic arc source. Therefore, we suggest that the Kunlun-Qinling terrane is most likely to have supplied source materials to the northeast part of the Songpan-Ganzi Basin during the Late Triassic.展开更多
Coal-based olefin(CTO)industry as a complement of traditional petrochemical industry plays vital role in China’s national economic development.However,high CO2 emission in CTO industry is one of the fatal problems to...Coal-based olefin(CTO)industry as a complement of traditional petrochemical industry plays vital role in China’s national economic development.However,high CO2 emission in CTO industry is one of the fatal problems to hinder its development.In this work,the carbon emission and mitigation potentials by different reduction pathways are evaluated.The economic cost is analyzed and compared as well.According to the industry development plan,the carbon emissions from China’s CTO industry will attain 189.43 million ton C02(MtC02)and 314.11 MtC02 in 2020 and 2030,respectively.With the advanced technology level,the maximal carbon mitigation potential could be attained to 15.3%and 21.9%in 2020 and 2030.If the other optional mitigation ways are combined together,the carbon emission could further reduce to some extent.In general,the order of mitigation potential is followed as:feedstock alteration by natural gas>C02 hydrogenation with renewable electricity applied>CCS technology.The mitigation cost analysis indicates that on the basis of 2015 situation,the economic penalty for feedstock alteration is the lowest,ranged between 186 and 451 CNY/tCO2,and the cost from CCS technology is ranged between 404 and 562 CNY/tC02,which is acceptable if the C02 enhanced oil recovery and carbon tax are considered.However,for the C02 hydrogenation technology,the cost is extremely high and there is almost no application possibility at present.展开更多
The rates of soil N mineralization at soil depths of 0-15, 15-30, 30-45 and45-60 cm and moisture regimes were measured at three sand-fixation plantations of Pinus sylvestrisvar. mongolica by laboratory aerobic incubat...The rates of soil N mineralization at soil depths of 0-15, 15-30, 30-45 and45-60 cm and moisture regimes were measured at three sand-fixation plantations of Pinus sylvestrisvar. mongolica by laboratory aerobic incubation method. The results showed that average rates ofsoil net N-mineralization across soil depth varied from 1.06 to 7.52 mg · kg^(-1)·month^(-1) atsoil depths from 0 to 60 cm. Statistical analyses indicated that the effects of different soildepths, moistures and their interactions on net N-mineralization rates were significant (P < 0.05).The net N-mineralization rates significantly decreased with increasing soil depths and at depth 0-15cm accounted for 60.52% of that at depth of 0-60 cm. There was no difference in soil netN-mineralization rates between half and fully-saturated water treatments, however these rates weresubstantially higher than that without water treatment (P < 0.05). The factors influencing Nmineralization process have to be studied further in these semiarid pine ecosystems.展开更多
Lithium elemental and isotopic disequilibrium has frequently been observed in the continental and oceanic mantle xenoliths, but its origin remains controversial. Here,we present a combined elemental and Li isotopic st...Lithium elemental and isotopic disequilibrium has frequently been observed in the continental and oceanic mantle xenoliths, but its origin remains controversial. Here,we present a combined elemental and Li isotopic study on variably metasomatised peridotite xenoliths entrained in the Cenozoic basalts from Shangzhi in Northeast (NE) China that provides insight into this issue. Li concentration (0.3–2.7 ppm) and δ7 Li (mostly 2‰–6‰) in olivine from the Shangzhi peridotites are similar to the normal mantle values and show roughly negative correlations with the indices of melt extraction(such as modal olivine and whole rock MgO). These features are consistent with variable degrees of partial melting. In contrast, clinopyroxene from the Shangzhi xenoliths shows significant Li enrichment (0.9–6.1 ppm) and anomalously light δ7 Li (-13.8‰ to7.7‰) relative to normal mantle values. Such features can be explained by Li diffusion from silicate melts or Li-rich fluids occurring over a very short time(several minutes to several hours). Moreover, the light Li isotopic compositions preserved in some bulk samples also indicate that these percolated melts/fluids have not had enough time to isotopically equilibrate with the bulk peridotite. We thus emphasize that Li isotopic fractionation in the Shangzhi mantle xenoliths is mainly related to Li diffusion from silicate melts or Li-rich fluids that took place shortly before or coincident with their entrainment into the host magmas.展开更多
Osteoporosis represents a prevalent and debilitating comorbidity in patients diagnosed with type 2 diabetes mellitus(T2DM),which is characterized by suppressed osteoblast function and disrupted bone microarchitecture....Osteoporosis represents a prevalent and debilitating comorbidity in patients diagnosed with type 2 diabetes mellitus(T2DM),which is characterized by suppressed osteoblast function and disrupted bone microarchitecture.In this study,we utilized male C57BL/6 J mice to investigate the role of SIRT3 in T2DM.Decreased SIRT3 expression and impaired mitochondrial quality control mechanism are observed in both in vitro and in vivo models of T2DM.Mechanistically,SIRT3 suppression results in hyperacetylation of FOXO3,hindering the activation of the PINK1/PRKN mediated mitophagy pathway and resulting in accumulation of dysfunctional mitochondria.Genetical overexpression or pharmacological activation of SIRT3 restores deacetylation status of FOXO3,thus facilitating mitophagy and ameliorating osteogenic impairment in T2DM.Collectively,our findings highlight the fundamental regulatory function of SIRT3 in mitochondrial quality control,crucial for maintaining bone homeostasis in T2DM.These insights not only enhance our understanding of the molecular mechanisms underlying diabetic osteoporosis but also identify SIRT3 as a promising therapeutic target for diabetic osteoporosis.展开更多
MPI （microwave polarization index） method can use different frequencies at vertical polarization to retrieve soil moisture from TMI （tropical microwave imager） data, which is mainly suitable for bare soil. This pa...MPI （microwave polarization index） method can use different frequencies at vertical polarization to retrieve soil moisture from TMI （tropical microwave imager） data, which is mainly suitable for bare soil. This paper makes an improvement for MPI method which makes it suitable for surface covered by vegetation. The MPI by using single frequency at different polarizations is used to discriminate the bare soil and vegetation which overcomes the difficulty in previous algorithms by using optical remote sensing data, and then the revision is made according to the different land surface types. The validation by using ground measurement data indicates that revision for different land surface types can improve the retrieval accuracy. The average error is about 24.5% by using the ground truth data obtained from ground observation stations, and the retrieval error is about 13.7% after making a revision by using ground measurement data from local observation stations for different surface types. The improved MPI method and precipitation are used to analyze the drought in Southwest China, and the analysis indicates the soil moisture retrieved by improved MPI method can be used to monitor the drought.展开更多
Improving and optimizing the target properties of ceramics via the high entropy strategy has attracted significant attention.Rare earth niobate is a potential thermal barrier coating(TBCs)material,but its poor high-te...Improving and optimizing the target properties of ceramics via the high entropy strategy has attracted significant attention.Rare earth niobate is a potential thermal barrier coating(TBCs)material,but its poor high-temperature phase stability limits its further application.In this work,four sets of TBCs high-entropy ceramics,(Sm_(1/5)Dy_(1/5)Ho_(1/5)Er_(1/5)Yb_(1/5))(Nb_(1/2)Ta_(1/2))O_(4)(5NbTa),(Sm_(1/6)Dy_(1/6)Ho_(1/6)Er_(1/6)Yb_(1/6)Lu_(1/6))(Nb_(1/2)Ta_(1/2))O_(4)(6NbTa),(Sm_(1/7)Gd_(1/7)Dy_(1/7)Ho_(1/7)Er_(1/7)Yb_(1/7)Lu_(1/7))(Nb_(1/2)Ta_(1/2))O_(4)(7NbTa),(Sm_(1/8)Gd_(1/8)Dy_(1/8)Ho_(1/8)Er_(1/8)Tm_(1/8)Yb_(1/8)Lu_(1/8))(Nb_(1/2)Ta_(1/2))O_(4)(8NbTa)are synthesized using a solid-state reaction method at 1650℃for 6 h.Firstly,the X-ray diffractometer(XRD)patterns display that the samples are all single-phase solid solution structures(space group C 2/c).Differential scanning calorimetry(DSC)and the high-temperature XRD of 8NbTa cross-check that the addition of Ta element in 8HERN increases the phase transition temperature above 1400℃,which can be attributed to that the Ta/Nb co-doping at B site introduces the fluctuation of the bond strength of Ta-O and Nb-O.Secondly,compared to high-entropy rare-earth niobates,the introduction of Ta atoms at B site substantially reduce thermal conductivity(re-duced by 44%,800℃)with the seven components high entropy ceramic as an example.The low thermal conductivity means strong phonon scattering,which may originate from the softening acoustic mode and flattened phonon dispersion in 5–8 principal element high entropy rare earth niobium tantalates(5–8NbTa)revealed by the first-principles calculations.Thirdly,the Ta/Nb co-doping in 5–8NbTa systems can further optimize the insulation performance of oxygen ions.The oxygen-ion conductivity of 8NbTa(3.31×10^(−6)S cm^(−1),900℃)is about 5 times lower than that of 8HERN(15.8×10^(−6)S cm^(−1),900℃)because of the sluggish diffusion effect,providing better oxygen barrier capacity in 5–8NbTa systems to inhibit the overgrowth of the thermal growth oxide(TGO)of TBCs.In addition,influenced by lattice dis-tortion and solid solution strengthening,the samples possess higher hardness(7.51–8.15 GPa)and TECs(9.78×10^(−6)K−1^(-1)0.78×10^(−6)K^(−1),1500℃)than the single rare-earth niobates and tantalates.Based on their excellent overall properties,it is considered that 5–8NbTa can be used as auspicious TBCs.展开更多
Two sets of alloys,Mg-Zn-Ca-xNi(0≤x≤5),have been developed with tunable corrosion and mechanical properties,optimized for fracturing materials.High-zinc artificial aged(T6)Mg-12Zn-0.5Ca-x Ni(0≤x≤5)series,featuring...Two sets of alloys,Mg-Zn-Ca-xNi(0≤x≤5),have been developed with tunable corrosion and mechanical properties,optimized for fracturing materials.High-zinc artificial aged(T6)Mg-12Zn-0.5Ca-x Ni(0≤x≤5)series,featuring a straightforward preparation method and the potential for manufacturing large-scale components,exhibit notable corrosion rates up to 29 mg cm^(-2)h^(-1)at 25℃ and 643 mg cm^(-2)h^(-1)at 93℃.The high corrosion rate is primary due to the Ni–containing second phases,which intensify the galvanic corrosion that overwhelms their corrosion barrier effect.Low-zinc rolled Mg-1.5Zn-0.2Ca-x Ni(0≤x≤5)series,characterizing excellent deformability with an elongation to failure of~26%,present accelerated corrosion rates up to 34 mg cm^(-2)h^(-1)at 25℃ and 942 mg cm^(-2)h^(-1)at 93℃.The elimination of corrosion barrier effect via deformation contributes to the further increase of corrosion rate compared to the T6 series.Additionally,Mg-Zn-Ca-xNi(0≤x≤5)alloys exhibit tunable ultimate tensile strengths ranging from~190 to~237 MPa,depending on their specific composition.The adjustable corrosion rate and mechanical properties render the Mg-Zn-Ca-x Ni(0≤x≤5)alloys suitable for fracturing materials.展开更多
Rolled Mg-Al-Sn series alloys generally possess limited formability due to the formation of strong basal texture.Texture weakening is an effective way to enhance formability,but usually accompanied with decreasing str...Rolled Mg-Al-Sn series alloys generally possess limited formability due to the formation of strong basal texture.Texture weakening is an effective way to enhance formability,but usually accompanied with decreasing strength.In this work,synergistic enhancement of strength and formability is achieved in a Mg-3Al-1Sn-0.5Ca-0.1Sm(ATXS3110)alloy by 0.2 wt.%Mn addition combined with high temperature rolling,exhibiting a high index Erichsen(I.E.)value of~8.1 mm and near-isotropic mechanical properties.On one hand,after Mn addition,the grain refinement from~7.6μm to~4.1μm results in suppression of extension twinning,thereby preventing the development of strong basal texture upon stretch forming.On the other hand,trace Mn addition narrows the grain size distribution and promotes the formation of uniform fine grains,which induces homogeneous deformation during stretch forming.Moreover,grain refinement and high-density nano-sized precipitates caused by trace Mn addition increase the strength.This work may provide insights into designing low-cost Mg-Al-Sn series alloys with superior comprehensive mechanical properties for further structural applications.展开更多
Biliary system,which is responsible for transporting bile from the liver into the intestine,is commonly damaged by inflammation or tumors eventually causing liver failure or death.The implantation of biliary stents ca...Biliary system,which is responsible for transporting bile from the liver into the intestine,is commonly damaged by inflammation or tumors eventually causing liver failure or death.The implantation of biliary stents can effectively alleviate both benign and malignant biliary strictures,but the plastic and metal stents that are currently used cannot degrade and nearly has no beneficial biological effects,therefore their long-term service can result into inflammation,the formation of sludges and re-obstruction of bile duct.In recent years,magnesium(Mg)metal has been received increasing attention in the field of biomedical application due to its excellent biocompatibility,adequate mechanical properties,biodegradability and other advantages,such as anti-inflammatory and anti-tumor properties.The research on biliary stents made of magnesium metals(BSMM)has also made significant progress and a series of experiments in vitro and vivo has proved their possibility.However,there are still some problems holding back BSMM’s clinical use,including rapid corrosion rate and potential harmful reaction.In this review,we would summarize the current research of BSMM,evaluate their clinical benefits,find the choke points,and discuss the solving method.展开更多
Precipitation via thermal treatments is among the most effective approaches to strengthening and is widely applied in the Al industry. Thermal treatments combined with deformation are capable of finely regulating the ...Precipitation via thermal treatments is among the most effective approaches to strengthening and is widely applied in the Al industry. Thermal treatments combined with deformation are capable of finely regulating the process of precipitation and distribution of precipitates. Deformation-induced defects exert significant impacts on the precipitation and already present precipitates, which however is often overlooked. In this study, the interactions between deformation and precipitation/precipitates, and their impacts on mechanical properties were systematically investigated in the solution-treated (ST) Al-0.61Mg-1.17Si-0.5Cu (wt.%), processed by multi-pass equal channel angular pressing (ECAP) and thermal treatments. Novel deformation-mediated cyclic evolution of precipitates is discovered: ST→ (1,2 passes: deformation induced precipitation) Guinier Preston (GP) zones→ (An250/30) Q’ and L phases→ (3-pass: deformation induced fragmentation/resolution) spherical precipitates→ (4-pass: deformation induced further fragmentation/resolution) GP zones. On this basis, we extend the quasi-binary phase diagram of Al-Mg_(2)Si along deformation as the third dimension and construct an innovative defect phase diagram for the Al-Mg-Si-based system. To testify to the effect of deformation-mediated cyclic evolution of precipitation/precipitates on the optimum mechanical properties, peak-aging treatments were performed in samples of ST and 3-pass states. Based on the microscopic characterizations, a distinctive mechanism of peak-aging strengthening is proposed. Notably in the 3-pass ECAPed and peak-aged sample the dominant strengthening phases become the L precipitates that thrived from the segmented and spherical L phases, rather than β’’ precipitates in the solely peak-aged ST sample. Our work provides a feasible example for exploring the combined processing technique of multi-step deformation and thermal treatments, to optimize the mechanical properties.展开更多
Pre-stretching and annealing treatments were conducted on twin roll cast Mg-2Al-1Zn-1Ca(AZX211,in wt.%)plates with a rare earth-like texture.Varying amounts of deformation were applied along the rolling direction(RD)a...Pre-stretching and annealing treatments were conducted on twin roll cast Mg-2Al-1Zn-1Ca(AZX211,in wt.%)plates with a rare earth-like texture.Varying amounts of deformation were applied along the rolling direction(RD)and transverse direction(TD)of AZX211 alloy in order to modify its mechanical proper-ties at room temperature.The results demonstrate that pre-stretching treatment effectively enhances the yield strength(YS),especially along the RD.The strengthening mechanism is attributed to the production of a large number of dislocations and sub-grain boundaries,but the work-hardening ability of the plate will be greatly weakened.Additionally,annealing treatment substantially improves the plasticity and in-plane anisotropy and restores the work-hardening ability.The notable distinction in the pre-stretching process between different directions lies in the underlying deformation mechanism.In case of RD,de-formation is predominantly governed by the slip mechanism of{0002}{11−20}basal slip and{10−10}{11−20}prismatic slip,while along the TD,deformation is primarily controlled by{0002}{11−20}basal slip without significant twinning deformation.When a 6%pre-stretching is conducted,the initial rare earth-like texture of the sample transforms into a symmetrically distributed double-peak basal texture,accompanied by grain refinement.This texture transformation is chiefly due to the dominance of{0002}{11−20}basal slip-driven deformation.Moreover,the annealed sample maintains a strong basal texture,owing to strain-induced recrystallization.展开更多
Graphene,as the reinforcing phase of magnesium matrix composites,can effectively improve the material strength,elastic modulus,and other properties.However,the random distribution of graphene in the matrix(i.e.,random...Graphene,as the reinforcing phase of magnesium matrix composites,can effectively improve the material strength,elastic modulus,and other properties.However,the random distribution of graphene in the matrix(i.e.,random orientation angle)leads to different reinforcement effects on the matrix.To gain a deeper understanding of the impact of monolayer graphene(1 LG)with varying orientation angles on the properties of Mg-9 Al-1 Zn(AZ91(wt.%))magnesium alloy,molecular dynamics(MD)simulations are employed to analyze the mechanical properties of AZ91/1 LG composites under uniaxial tension.The simulation results show that Young's modulus and tensile strength of AZ91/1 LG composites decrease gradually with the increase of the orientation angle of the 1 LG.The Young's modulus and tensile strength of AZ91/1 LG composites can be improved by the 1 LG orientation angle of 0°~10°,where the two are enhanced by 21.7%and 19.7%respectively,at an orientation angle of 0°.However,the Young's modulus and tensile strength of 1 LG are decreased for orientation angles of 20°~90°.Atomic structure evolution analysis revealed that the deformation mechanism of AZ91/1 LG nanocomposites mainly depended on the load transfer ability of 1 LG with different orientation angles,the bonding ability with AZ91 magnesium alloy matrix and the change of dislocation density.By fitting the formula to the tensile strength of AZ91/1 LG composites with different orientation angles of 1 LG,it is found that the simulated data of the AZ91/1 LG composites containing a 1 LG has a maximum relative error of about 10%concerning the fitted empirical formula to calculate the data.The maximum relative error for AZ91/1 LG composites containing multiplate 1 LG with different orientation angles is 7%.In addition,the interaction between graphene and dislocations in AZ91 magnesium matrix was further explained by transmission electron microscopy(TEM)and phase-field-crystal(PFC)simulation.It can provide some technical guidance for the experimental process design of AZ91/1 LG composites.展开更多
This study analyzes the potential impact of EU carbon border regulation mechanism(CBAM)on the export of China’s carbon-intensive products.First,we summarized the main content of the CBAM.Next,based on the input-outpu...This study analyzes the potential impact of EU carbon border regulation mechanism(CBAM)on the export of China’s carbon-intensive products.First,we summarized the main content of the CBAM.Next,based on the input-output theory,this study proposes a calculation model for the implicit carbon emissions and indirect carbon emissions from electricity consumption in export products and presents the corresponding calculation results.Based on the scenario analysis method,six carbon tariffscenarios were designed to evaluate the impact of the CBAM on the major export sectors under each scenario.The results showed that in 2021,the implicit carbon emissions in all products exported to Europe from China were approximately 375 million tons,of which the indirect carbon emissions from electricity were approximately 41.8 million tons,accounting for more than 10%.According to the current levy plan,China is expected to be subject to carbon tariffs of approximately USD 1.4 billion,accounting for 0.3%of its total export value to Europe in 2021.Finally,to reduce the adverse effects of CBAM,four measures were proposed from the perspective of the power industry.展开更多
Mg alloy matrix composites reinforced with short carbon fibers(C_(sf)/Mg)are considered as potential candidates for integrated structural-functional electronic parts that satisfy the requirements of lightweight,excell...Mg alloy matrix composites reinforced with short carbon fibers(C_(sf)/Mg)are considered as potential candidates for integrated structural-functional electronic parts that satisfy the requirements of lightweight,excellent mechanical properties,and heat dissipation.However,the different characteristics of C_(sf)and Mg alloy make the interface a critical issue affecting the synergistic improvement of thermal and mechanical properties of the composites.Here,Cu coating with different thicknesses is introduced to modify the C_(sf)/Mg interface,so as to simultaneously enhance the thermal and mechanical performances,which can combine the advantages of coating modification and matrix alloying.Results reveal that thermal diffusivity(TD)of 3-C_(sf)-Cu/Mg composites is as high as 22.12 mm^(2)/s and an enhancement of 52.97%is achieved compared with C_(sf)/Mg composites,as well as 16.3%enhancement of ultimate compressive strength(UCS)in the longitudinal direction,8.84%improvement of UCS in the transverse direction,and 53.08%increasement of ultimate tensile strength(UTS).Such improvement can be ascribed to the formation of intermetallic compounds.The formation of intermetallic compounds can not only effectively alleviate the lattice distortion of the matrix and decrease interfacial thermal resistance,but also bear the loads.Our work is of great significance for designing C_(sf)/Mg composites with integrated structure and function.展开更多
Since the concept of artificial psychology and artificial emotion was first presented, it has become a topic of interest in academic circles and enterprises. In this article, we first briefly introduce the basic conce...Since the concept of artificial psychology and artificial emotion was first presented, it has become a topic of interest in academic circles and enterprises. In this article, we first briefly introduce the basic concepts and principles of artificial psychology and artificial emotion, analyzing the unified macro-model of the cross-disciplinary system architecture against the need-motivation-behavior framework. Second, we discuss the origin of artificial psychology and artificial emotion, its course of development, and its present situation in China. We also present a review of the published papers and research endeavors of Chinese universities and research institutions and the technical engineering applications of artificial psychology and artificial emotion. Finally, we summarize the challenges to the further development of artificial psychology and artificial emotion and our recommendations for improving the cognitive computing model of psychological states and developing reliable and accurate humanoid interaction and cooperation technology, robot platforms with emotions and humanoid interaction and cooperation capabilities, and humanoid robots for the elderly and the disabled in smart homes. We believe that, with intensive research, artificial psychology and artificial emotion may be developed further and may eventually reach maturity.展开更多
基金funded by the National Natural Science Foundation of China(42125203,42330809)the 111 project of the Ministry of Science and Technology(BP0719021).
文摘The Cretaceous gold deposits along the margins of the North China Craton(NCC),which formed in a craton destruction setting,display geological characteristics similar to traditional orogenic gold deposits typically associated with accretionary orogeny.These deposits,known as Jiaodong-type gold deposits,have attracted considerable attention.However,the lithospheric controls and formation mechanisms of these deposits remain unclear,as they cannot be fully explained by the supracrustal metamorphic genetic model commonly applied to classic orogenic gold deposits.In this study,the compiled S-Hg-Pb isotope ratios of gold deposits on different NCC margins display compatible variations to the Sr-Nd-Hg isotope ratios of mafic dikes spatial-temporally associated with the deposits.This implies that mantle lithosphere,metasomatized by variable proportions of oceanic and continental crust,was the source for both gold deposits and mafic dikes.Increase of oxygen fugacity and zirconεHf(t)from pre-to syn-gold granites suggests continuous basic magma underplating,which could induce concentrations of Au-rich sulfides and contribute additional Au to auriferous CO_(2)-rich fluids derived from metasomatized mantle lithosphere and basic magma.Localization of gold deposits was controlled by craton-margin sinistral shearing induced by clockwise rotation of the craton coincident with distal emplacement of metamorphic core complexes.Thus,the Cretaceous Jiaodong-type orogenic gold deposits were derived from fertilized mantle lithosphere through such crust-mantle processes within a lithosphere thinning background.
基金supported by The National Natural Science Foundation of China(42303060)The China Scholarship Council(CSC,201906250131).
文摘Regolith,widely distributed on the Earth’s surface,constitutes a significant compartment of the Critical Zone,resulting from intricate interactions among the atmosphere,lithosphere,hydrosphere,and biosphere.Regolith formation critically influences nutrient release,soil production,and long-term climate regulation.Regolith development is governed by two primary processes:production and denudation.An urgent need exists to comprehensively understand these processes to refine our understanding of Critical Zone functions.This study investigates an in-situ regolith profile developed on granitic bedrock from a tropical region(Sanya,China).We conducted geochemical analyses,encompassing major,trace elements and mineralogical compositions as well as U-series isotopes,and applied the U-series disequilibrium method to investigate the formation history of this profile.Alternatively,dividing the regolith profile into sub-weathering zones provides a better explanation for the geochemical results,and a multi-stage model based on this subdivision effectively interprets the evolution of deep regolith.Utilizing this multi-stage model,regolith production rates is derived from the“gain and loss”model,ranging from 1.27±0.03 to 42.42±24.24 m/Ma.The production rates first increase from surface until a maximum rate is reached at the depth of∼160 cm and then decrease at further deeper horizons along the depth profile,and the variation of production rates follows a so-called“humped function”.This pioneering investigation into regolith production rates in the Chinese tropical region indicates that(1)the studied profile deviates from a steady state compared to the denudation rate derived from cosmogenic nuclides(^(10)Be_in-situ);(2)subdividing the deep profile based on geochemical data and U-series isotopic activity ratios is imperative for accurately determining regolith production rates;and(3)the combination of U-series disequilibrium and cosmogenic nuclides robustly evaluates the quantitative evolution state of regolith over long time scales.
文摘Investing in disaster risk reduction is crucial for minimizing the impacts of disasters.However,little is known about the factors that influence changes in investment levels over time.This study aims to identify the key socio-economic drivers behind increases and decreases in flood protection investment in People’s Republic of China(PRC).Such information is crucial for policy makers to justify flood investments.By analyzing data on flood protection expenditures,economic losses from floods,and other relevant indicators from 1980 to 2020,the study evaluates the relationship between investment and disaster impacts through the lens of the flood investment cycle model.It was found that the country succeeded in reducing flood damage because of increasing investment in flood protection.The results indicate that changes in PRC’s flood protection investment have been driven by three major factors:the occurrence of major disasters,the fiscal situation,and shifts in government policies.Investment tended to increase following large-scale events,such as the 1998 Yangtze River Basin flood and the 2008 Wenchuan earthquake,which prompted policy changes and renewed focus on DRR measures.Fiscal constraints limited investment in the 1990s,but reforms and stimulus measures improved the financial situation,enabling increased spending on flood protection.PRC’s experience in steadily reducing flood damage through sustained investment and policy commitment offers valuable lessons for other developing countries facing similar challenges.
文摘There is a need and opportunity for China to develop education and practice innovations given that advance practice nurses (APNs) improve health care and outcomes.The China Medical Board (CMB)China Nursing Network (CCNN) began planning for an Advanced Nursing Practice Program for education and career development that will facilitate CCNN's contributions to meeting national nursing policy priorities.This paper presents the discussion,recommendations and action plans developed at the inaugural planning meeting on June 26,2015 at Fudan University in Shanghai.The recommendations are:Develop standards for advanced nursing practice;Develop Master's level curricula based on the standards;Commence pilot projects across a number of University affiliated hospitals;and Prepare clinical tutors and faculty.The strategic directions and actions are: Develop a clinical career ladder system;Expand the nursing role from hospital to community;and Build a specialty nurse accreditation system.
基金supported by the SINOPEC Exploration Southern Company(the National Oil and Gas Special Projects XQ-04)the Special Fund for Basic Scientific Research of Central Colleges, Chang'an University(CHD2011JC185)
文摘Major, trace and rare earth element （REE） concentrations of Late Triassic sediments （fine- grained sandstones and mudstones） from Hongcan Well 1 in the NE part of the Songpan-Ganzi Basin, western China, are used to reveal weathering, provenance and tectonic setting of inferred source areas. The Chemical Index of Alteration （CIA） reflects a low to moderate degree of chemical weathering in a cool and somewhat dry climate, and an A-CN-K plot suggests an older upper continental crust prove- nance dominated by felsic to intermediate igneous rocks of average tonalite composition. Based on the various geochemical tectonic setting discrimination diagrams, the Late Triassic sediments are inferred to have been deposited in a back-arc basin situated between an active continental margin （the Kunlun- Qinling Fold Belt） and a continental island arc （the Yidun Island Arc）. The Triassic sediments in the study area underwent a rapid erosion and burial in a proximal slope-basin environment by the petrographic data,while the published flow directions of Triassic turbidites in the Aba-Zoige region was not supported Yidun volcanic arc source. Therefore, we suggest that the Kunlun-Qinling terrane is most likely to have supplied source materials to the northeast part of the Songpan-Ganzi Basin during the Late Triassic.
基金sponsored by the National Key Research and Development Program(No.2016YFA0602603,No.2016YFA0602602)Chinese Academy of Sciences Youth Innovation Promotion Association FundingShanghai Natural Science Foundation(No.18ZR1444200)
文摘Coal-based olefin(CTO)industry as a complement of traditional petrochemical industry plays vital role in China’s national economic development.However,high CO2 emission in CTO industry is one of the fatal problems to hinder its development.In this work,the carbon emission and mitigation potentials by different reduction pathways are evaluated.The economic cost is analyzed and compared as well.According to the industry development plan,the carbon emissions from China’s CTO industry will attain 189.43 million ton C02(MtC02)and 314.11 MtC02 in 2020 and 2030,respectively.With the advanced technology level,the maximal carbon mitigation potential could be attained to 15.3%and 21.9%in 2020 and 2030.If the other optional mitigation ways are combined together,the carbon emission could further reduce to some extent.In general,the order of mitigation potential is followed as:feedstock alteration by natural gas>C02 hydrogenation with renewable electricity applied>CCS technology.The mitigation cost analysis indicates that on the basis of 2015 situation,the economic penalty for feedstock alteration is the lowest,ranged between 186 and 451 CNY/tCO2,and the cost from CCS technology is ranged between 404 and 562 CNY/tC02,which is acceptable if the C02 enhanced oil recovery and carbon tax are considered.However,for the C02 hydrogenation technology,the cost is extremely high and there is almost no application possibility at present.
基金This paper was supported by National Natural Science Foundation of China (30471377), the Chinese Academy of Sciences (Knowledge Innovation Project KZCX3-SW-418), and the Institute of Applied Ecology of Chinese Academy of Sciences (SLYQY0409).
文摘The rates of soil N mineralization at soil depths of 0-15, 15-30, 30-45 and45-60 cm and moisture regimes were measured at three sand-fixation plantations of Pinus sylvestrisvar. mongolica by laboratory aerobic incubation method. The results showed that average rates ofsoil net N-mineralization across soil depth varied from 1.06 to 7.52 mg · kg^(-1)·month^(-1) atsoil depths from 0 to 60 cm. Statistical analyses indicated that the effects of different soildepths, moistures and their interactions on net N-mineralization rates were significant (P < 0.05).The net N-mineralization rates significantly decreased with increasing soil depths and at depth 0-15cm accounted for 60.52% of that at depth of 0-60 cm. There was no difference in soil netN-mineralization rates between half and fully-saturated water treatments, however these rates weresubstantially higher than that without water treatment (P < 0.05). The factors influencing Nmineralization process have to be studied further in these semiarid pine ecosystems.
基金funded by the strategic priority research program(B)of the Chinese Academy of Sciences(XDB18000000)NSFC(41573009+1 种基金 41373042,41203031)Open research fund of the State Key Laboratory of Ore Deposit Geochemistry of China(SKLODG Grant#201204)
文摘Lithium elemental and isotopic disequilibrium has frequently been observed in the continental and oceanic mantle xenoliths, but its origin remains controversial. Here,we present a combined elemental and Li isotopic study on variably metasomatised peridotite xenoliths entrained in the Cenozoic basalts from Shangzhi in Northeast (NE) China that provides insight into this issue. Li concentration (0.3–2.7 ppm) and δ7 Li (mostly 2‰–6‰) in olivine from the Shangzhi peridotites are similar to the normal mantle values and show roughly negative correlations with the indices of melt extraction(such as modal olivine and whole rock MgO). These features are consistent with variable degrees of partial melting. In contrast, clinopyroxene from the Shangzhi xenoliths shows significant Li enrichment (0.9–6.1 ppm) and anomalously light δ7 Li (-13.8‰ to7.7‰) relative to normal mantle values. Such features can be explained by Li diffusion from silicate melts or Li-rich fluids occurring over a very short time(several minutes to several hours). Moreover, the light Li isotopic compositions preserved in some bulk samples also indicate that these percolated melts/fluids have not had enough time to isotopically equilibrate with the bulk peridotite. We thus emphasize that Li isotopic fractionation in the Shangzhi mantle xenoliths is mainly related to Li diffusion from silicate melts or Li-rich fluids that took place shortly before or coincident with their entrainment into the host magmas.
基金supported by the National Key Research and Development Project (2021YFA1201404)National Natural Science Foundation of China Major Project (81991514)+6 种基金General Project (82272530, 82372459)Jiangsu Province Medical Innovation Center of Orthopedic Surgery (CXZX202214)Jiangsu Provincial Key Medical Center FoundationJiangsu Provincial Medical Outstanding Talent FoundationJiangsu Provincial Medical Youth Talent FoundationJiangsu Provincial Key Medical Talent Foundationthe Fundamental Research Funds for the Central Universities (14380493, 14380494)
文摘Osteoporosis represents a prevalent and debilitating comorbidity in patients diagnosed with type 2 diabetes mellitus(T2DM),which is characterized by suppressed osteoblast function and disrupted bone microarchitecture.In this study,we utilized male C57BL/6 J mice to investigate the role of SIRT3 in T2DM.Decreased SIRT3 expression and impaired mitochondrial quality control mechanism are observed in both in vitro and in vivo models of T2DM.Mechanistically,SIRT3 suppression results in hyperacetylation of FOXO3,hindering the activation of the PINK1/PRKN mediated mitophagy pathway and resulting in accumulation of dysfunctional mitochondria.Genetical overexpression or pharmacological activation of SIRT3 restores deacetylation status of FOXO3,thus facilitating mitophagy and ameliorating osteogenic impairment in T2DM.Collectively,our findings highlight the fundamental regulatory function of SIRT3 in mitochondrial quality control,crucial for maintaining bone homeostasis in T2DM.These insights not only enhance our understanding of the molecular mechanisms underlying diabetic osteoporosis but also identify SIRT3 as a promising therapeutic target for diabetic osteoporosis.
基金supported by the National Basic Research Program of China (2010CB951503)the National Natural Science Foundation of China(40930101)+2 种基金the Open Fund of the State Key Laboratory of Remote Sensing Sciencejointly sponsored by the Institute of Remote Sensing Applications of the Chinese Academy of Sciences and Beijing Normal University, Chinathe Open Fund of Key Laboratory of Agrometeorological Safeguard and Applied, China Meteorological Administration
文摘MPI （microwave polarization index） method can use different frequencies at vertical polarization to retrieve soil moisture from TMI （tropical microwave imager） data, which is mainly suitable for bare soil. This paper makes an improvement for MPI method which makes it suitable for surface covered by vegetation. The MPI by using single frequency at different polarizations is used to discriminate the bare soil and vegetation which overcomes the difficulty in previous algorithms by using optical remote sensing data, and then the revision is made according to the different land surface types. The validation by using ground measurement data indicates that revision for different land surface types can improve the retrieval accuracy. The average error is about 24.5% by using the ground truth data obtained from ground observation stations, and the retrieval error is about 13.7% after making a revision by using ground measurement data from local observation stations for different surface types. The improved MPI method and precipitation are used to analyze the drought in Southwest China, and the analysis indicates the soil moisture retrieved by improved MPI method can be used to monitor the drought.
基金support from Yunnan Major Scientific and Technological Projects(No.202302AG050010)Yunnan Fundamental Research Projects(Nos.202101AW070011 and202101BE070001–015)+1 种基金National Natural Science Foundation of China(No.52303295)Project Funds of“Xingdian Talent Support Program”.
文摘Improving and optimizing the target properties of ceramics via the high entropy strategy has attracted significant attention.Rare earth niobate is a potential thermal barrier coating(TBCs)material,but its poor high-temperature phase stability limits its further application.In this work,four sets of TBCs high-entropy ceramics,(Sm_(1/5)Dy_(1/5)Ho_(1/5)Er_(1/5)Yb_(1/5))(Nb_(1/2)Ta_(1/2))O_(4)(5NbTa),(Sm_(1/6)Dy_(1/6)Ho_(1/6)Er_(1/6)Yb_(1/6)Lu_(1/6))(Nb_(1/2)Ta_(1/2))O_(4)(6NbTa),(Sm_(1/7)Gd_(1/7)Dy_(1/7)Ho_(1/7)Er_(1/7)Yb_(1/7)Lu_(1/7))(Nb_(1/2)Ta_(1/2))O_(4)(7NbTa),(Sm_(1/8)Gd_(1/8)Dy_(1/8)Ho_(1/8)Er_(1/8)Tm_(1/8)Yb_(1/8)Lu_(1/8))(Nb_(1/2)Ta_(1/2))O_(4)(8NbTa)are synthesized using a solid-state reaction method at 1650℃for 6 h.Firstly,the X-ray diffractometer(XRD)patterns display that the samples are all single-phase solid solution structures(space group C 2/c).Differential scanning calorimetry(DSC)and the high-temperature XRD of 8NbTa cross-check that the addition of Ta element in 8HERN increases the phase transition temperature above 1400℃,which can be attributed to that the Ta/Nb co-doping at B site introduces the fluctuation of the bond strength of Ta-O and Nb-O.Secondly,compared to high-entropy rare-earth niobates,the introduction of Ta atoms at B site substantially reduce thermal conductivity(re-duced by 44%,800℃)with the seven components high entropy ceramic as an example.The low thermal conductivity means strong phonon scattering,which may originate from the softening acoustic mode and flattened phonon dispersion in 5–8 principal element high entropy rare earth niobium tantalates(5–8NbTa)revealed by the first-principles calculations.Thirdly,the Ta/Nb co-doping in 5–8NbTa systems can further optimize the insulation performance of oxygen ions.The oxygen-ion conductivity of 8NbTa(3.31×10^(−6)S cm^(−1),900℃)is about 5 times lower than that of 8HERN(15.8×10^(−6)S cm^(−1),900℃)because of the sluggish diffusion effect,providing better oxygen barrier capacity in 5–8NbTa systems to inhibit the overgrowth of the thermal growth oxide(TGO)of TBCs.In addition,influenced by lattice dis-tortion and solid solution strengthening,the samples possess higher hardness(7.51–8.15 GPa)and TECs(9.78×10^(−6)K−1^(-1)0.78×10^(−6)K^(−1),1500℃)than the single rare-earth niobates and tantalates.Based on their excellent overall properties,it is considered that 5–8NbTa can be used as auspicious TBCs.
基金supported by the National Key Research and Development Program(No.2022YFE0122000)National Natural Science Foundation of China under Grant Nos.52234009,52274383,52222409,and 52201113。
文摘Two sets of alloys,Mg-Zn-Ca-xNi(0≤x≤5),have been developed with tunable corrosion and mechanical properties,optimized for fracturing materials.High-zinc artificial aged(T6)Mg-12Zn-0.5Ca-x Ni(0≤x≤5)series,featuring a straightforward preparation method and the potential for manufacturing large-scale components,exhibit notable corrosion rates up to 29 mg cm^(-2)h^(-1)at 25℃ and 643 mg cm^(-2)h^(-1)at 93℃.The high corrosion rate is primary due to the Ni–containing second phases,which intensify the galvanic corrosion that overwhelms their corrosion barrier effect.Low-zinc rolled Mg-1.5Zn-0.2Ca-x Ni(0≤x≤5)series,characterizing excellent deformability with an elongation to failure of~26%,present accelerated corrosion rates up to 34 mg cm^(-2)h^(-1)at 25℃ and 942 mg cm^(-2)h^(-1)at 93℃.The elimination of corrosion barrier effect via deformation contributes to the further increase of corrosion rate compared to the T6 series.Additionally,Mg-Zn-Ca-xNi(0≤x≤5)alloys exhibit tunable ultimate tensile strengths ranging from~190 to~237 MPa,depending on their specific composition.The adjustable corrosion rate and mechanical properties render the Mg-Zn-Ca-x Ni(0≤x≤5)alloys suitable for fracturing materials.
基金supported by The National Natural Science Foundation of China(under Nos.52234009,U19A2084,52171116,U22A20109,52201113)Partial financial support came from Program for the Central University Youth Innovation Team(419021423505)+2 种基金the Fundamental Research Funds for the Central Universities(No.2412022QD037)the Excellent Youth Program of Jilin Provincial Department of Education(JJKH20241425KJ)the Fundamental Research Funds for the Central Universities,JLU.
文摘Rolled Mg-Al-Sn series alloys generally possess limited formability due to the formation of strong basal texture.Texture weakening is an effective way to enhance formability,but usually accompanied with decreasing strength.In this work,synergistic enhancement of strength and formability is achieved in a Mg-3Al-1Sn-0.5Ca-0.1Sm(ATXS3110)alloy by 0.2 wt.%Mn addition combined with high temperature rolling,exhibiting a high index Erichsen(I.E.)value of~8.1 mm and near-isotropic mechanical properties.On one hand,after Mn addition,the grain refinement from~7.6μm to~4.1μm results in suppression of extension twinning,thereby preventing the development of strong basal texture upon stretch forming.On the other hand,trace Mn addition narrows the grain size distribution and promotes the formation of uniform fine grains,which induces homogeneous deformation during stretch forming.Moreover,grain refinement and high-density nano-sized precipitates caused by trace Mn addition increase the strength.This work may provide insights into designing low-cost Mg-Al-Sn series alloys with superior comprehensive mechanical properties for further structural applications.
基金supported by Natural Science Foundation of Hunan Province(2021JJ31081,2024JJ5619)the Science Fund of State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle(No 32215004).
文摘Biliary system,which is responsible for transporting bile from the liver into the intestine,is commonly damaged by inflammation or tumors eventually causing liver failure or death.The implantation of biliary stents can effectively alleviate both benign and malignant biliary strictures,but the plastic and metal stents that are currently used cannot degrade and nearly has no beneficial biological effects,therefore their long-term service can result into inflammation,the formation of sludges and re-obstruction of bile duct.In recent years,magnesium(Mg)metal has been received increasing attention in the field of biomedical application due to its excellent biocompatibility,adequate mechanical properties,biodegradability and other advantages,such as anti-inflammatory and anti-tumor properties.The research on biliary stents made of magnesium metals(BSMM)has also made significant progress and a series of experiments in vitro and vivo has proved their possibility.However,there are still some problems holding back BSMM’s clinical use,including rapid corrosion rate and potential harmful reaction.In this review,we would summarize the current research of BSMM,evaluate their clinical benefits,find the choke points,and discuss the solving method.
基金supported by the National Natural Science Foundation of China(Grant Nos.U22A20187,52171007,52371111,and 52371177).
文摘Precipitation via thermal treatments is among the most effective approaches to strengthening and is widely applied in the Al industry. Thermal treatments combined with deformation are capable of finely regulating the process of precipitation and distribution of precipitates. Deformation-induced defects exert significant impacts on the precipitation and already present precipitates, which however is often overlooked. In this study, the interactions between deformation and precipitation/precipitates, and their impacts on mechanical properties were systematically investigated in the solution-treated (ST) Al-0.61Mg-1.17Si-0.5Cu (wt.%), processed by multi-pass equal channel angular pressing (ECAP) and thermal treatments. Novel deformation-mediated cyclic evolution of precipitates is discovered: ST→ (1,2 passes: deformation induced precipitation) Guinier Preston (GP) zones→ (An250/30) Q’ and L phases→ (3-pass: deformation induced fragmentation/resolution) spherical precipitates→ (4-pass: deformation induced further fragmentation/resolution) GP zones. On this basis, we extend the quasi-binary phase diagram of Al-Mg_(2)Si along deformation as the third dimension and construct an innovative defect phase diagram for the Al-Mg-Si-based system. To testify to the effect of deformation-mediated cyclic evolution of precipitation/precipitates on the optimum mechanical properties, peak-aging treatments were performed in samples of ST and 3-pass states. Based on the microscopic characterizations, a distinctive mechanism of peak-aging strengthening is proposed. Notably in the 3-pass ECAPed and peak-aged sample the dominant strengthening phases become the L precipitates that thrived from the segmented and spherical L phases, rather than β’’ precipitates in the solely peak-aged ST sample. Our work provides a feasible example for exploring the combined processing technique of multi-step deformation and thermal treatments, to optimize the mechanical properties.
基金supported by the National Natural Science Foundation of China(No.52001106)Hebei province(No.E2022202158).
文摘Pre-stretching and annealing treatments were conducted on twin roll cast Mg-2Al-1Zn-1Ca(AZX211,in wt.%)plates with a rare earth-like texture.Varying amounts of deformation were applied along the rolling direction(RD)and transverse direction(TD)of AZX211 alloy in order to modify its mechanical proper-ties at room temperature.The results demonstrate that pre-stretching treatment effectively enhances the yield strength(YS),especially along the RD.The strengthening mechanism is attributed to the production of a large number of dislocations and sub-grain boundaries,but the work-hardening ability of the plate will be greatly weakened.Additionally,annealing treatment substantially improves the plasticity and in-plane anisotropy and restores the work-hardening ability.The notable distinction in the pre-stretching process between different directions lies in the underlying deformation mechanism.In case of RD,de-formation is predominantly governed by the slip mechanism of{0002}{11−20}basal slip and{10−10}{11−20}prismatic slip,while along the TD,deformation is primarily controlled by{0002}{11−20}basal slip without significant twinning deformation.When a 6%pre-stretching is conducted,the initial rare earth-like texture of the sample transforms into a symmetrically distributed double-peak basal texture,accompanied by grain refinement.This texture transformation is chiefly due to the dominance of{0002}{11−20}basal slip-driven deformation.Moreover,the annealed sample maintains a strong basal texture,owing to strain-induced recrystallization.
基金supported by National Natural Science Foundation of China(Nos.52375394,52275390)Key Research and Development Program of Shanxi Province(Nos.202102050201011,2022ZDYF035)。
文摘Graphene,as the reinforcing phase of magnesium matrix composites,can effectively improve the material strength,elastic modulus,and other properties.However,the random distribution of graphene in the matrix(i.e.,random orientation angle)leads to different reinforcement effects on the matrix.To gain a deeper understanding of the impact of monolayer graphene(1 LG)with varying orientation angles on the properties of Mg-9 Al-1 Zn(AZ91(wt.%))magnesium alloy,molecular dynamics(MD)simulations are employed to analyze the mechanical properties of AZ91/1 LG composites under uniaxial tension.The simulation results show that Young's modulus and tensile strength of AZ91/1 LG composites decrease gradually with the increase of the orientation angle of the 1 LG.The Young's modulus and tensile strength of AZ91/1 LG composites can be improved by the 1 LG orientation angle of 0°~10°,where the two are enhanced by 21.7%and 19.7%respectively,at an orientation angle of 0°.However,the Young's modulus and tensile strength of 1 LG are decreased for orientation angles of 20°~90°.Atomic structure evolution analysis revealed that the deformation mechanism of AZ91/1 LG nanocomposites mainly depended on the load transfer ability of 1 LG with different orientation angles,the bonding ability with AZ91 magnesium alloy matrix and the change of dislocation density.By fitting the formula to the tensile strength of AZ91/1 LG composites with different orientation angles of 1 LG,it is found that the simulated data of the AZ91/1 LG composites containing a 1 LG has a maximum relative error of about 10%concerning the fitted empirical formula to calculate the data.The maximum relative error for AZ91/1 LG composites containing multiplate 1 LG with different orientation angles is 7%.In addition,the interaction between graphene and dislocations in AZ91 magnesium matrix was further explained by transmission electron microscopy(TEM)and phase-field-crystal(PFC)simulation.It can provide some technical guidance for the experimental process design of AZ91/1 LG composites.
文摘This study analyzes the potential impact of EU carbon border regulation mechanism(CBAM)on the export of China’s carbon-intensive products.First,we summarized the main content of the CBAM.Next,based on the input-output theory,this study proposes a calculation model for the implicit carbon emissions and indirect carbon emissions from electricity consumption in export products and presents the corresponding calculation results.Based on the scenario analysis method,six carbon tariffscenarios were designed to evaluate the impact of the CBAM on the major export sectors under each scenario.The results showed that in 2021,the implicit carbon emissions in all products exported to Europe from China were approximately 375 million tons,of which the indirect carbon emissions from electricity were approximately 41.8 million tons,accounting for more than 10%.According to the current levy plan,China is expected to be subject to carbon tariffs of approximately USD 1.4 billion,accounting for 0.3%of its total export value to Europe in 2021.Finally,to reduce the adverse effects of CBAM,four measures were proposed from the perspective of the power industry.
基金supported by the National Natural Science Foundation of China(grant no.52231004 and 52072305).
文摘Mg alloy matrix composites reinforced with short carbon fibers(C_(sf)/Mg)are considered as potential candidates for integrated structural-functional electronic parts that satisfy the requirements of lightweight,excellent mechanical properties,and heat dissipation.However,the different characteristics of C_(sf)and Mg alloy make the interface a critical issue affecting the synergistic improvement of thermal and mechanical properties of the composites.Here,Cu coating with different thicknesses is introduced to modify the C_(sf)/Mg interface,so as to simultaneously enhance the thermal and mechanical performances,which can combine the advantages of coating modification and matrix alloying.Results reveal that thermal diffusivity(TD)of 3-C_(sf)-Cu/Mg composites is as high as 22.12 mm^(2)/s and an enhancement of 52.97%is achieved compared with C_(sf)/Mg composites,as well as 16.3%enhancement of ultimate compressive strength(UCS)in the longitudinal direction,8.84%improvement of UCS in the transverse direction,and 53.08%increasement of ultimate tensile strength(UTS).Such improvement can be ascribed to the formation of intermetallic compounds.The formation of intermetallic compounds can not only effectively alleviate the lattice distortion of the matrix and decrease interfacial thermal resistance,but also bear the loads.Our work is of great significance for designing C_(sf)/Mg composites with integrated structure and function.
文摘Since the concept of artificial psychology and artificial emotion was first presented, it has become a topic of interest in academic circles and enterprises. In this article, we first briefly introduce the basic concepts and principles of artificial psychology and artificial emotion, analyzing the unified macro-model of the cross-disciplinary system architecture against the need-motivation-behavior framework. Second, we discuss the origin of artificial psychology and artificial emotion, its course of development, and its present situation in China. We also present a review of the published papers and research endeavors of Chinese universities and research institutions and the technical engineering applications of artificial psychology and artificial emotion. Finally, we summarize the challenges to the further development of artificial psychology and artificial emotion and our recommendations for improving the cognitive computing model of psychological states and developing reliable and accurate humanoid interaction and cooperation technology, robot platforms with emotions and humanoid interaction and cooperation capabilities, and humanoid robots for the elderly and the disabled in smart homes. We believe that, with intensive research, artificial psychology and artificial emotion may be developed further and may eventually reach maturity.
