Cemented paste backfill(CPB)has been one of the best practical approaches for tailings management and underground goaf treatment.Paste rheology is a science to study the flow and deformation behaviors of paste or fill...Cemented paste backfill(CPB)has been one of the best practical approaches for tailings management and underground goaf treatment.Paste rheology is a science to study the flow and deformation behaviors of paste or filling body under the effects of stress,strain,temperature,and time during the CPB process.The goal of studying paste rheology is to solve the engineering problems existing in four key processes;that is,paste rheology should meet the engineering demands of thickening,mixing,transportation,and backfilling.However,paste rheology is extremely complicated due to its high concentration,materials complexity,and engineering characteristics of non-stratification,nonsegregation,and non-bleeding.The rheological behavior of full tailings in deep thickening,rheological behavior of paste in mixing and pipeline transportation,and rheological behavior of filling body are introduced and discussed:(1)gel point,compressive yield stress,and the hindered settling function are adopted to characterize the rheological properties of full tailings in deep thickening.Combination of Coe-Clevenger theory and Buscall-White theory can also analyze the thickening performance in the whole area of deep cone thickener;(2)yield stress and viscosity are consistent with the evolution trend of the relative structure coefficient of paste in mixing;(3)coupling effect of wall slip and time-temperature dependency has a significant influence on the rheological properties and pipeline transportation;(4)damage variable is introduced to the Burgers model to describe the creep damage of the filling body.However,in-depth and systematic studies were still needed to establish a complete theoretical system of paste rheology in metal mines.展开更多
In the past decade, the sudden rise of high-entropy alloys(HEAs) has become a research hotspot in the domain of metal materials. HEAs break through the design concept of traditional single-principal element alloys, an...In the past decade, the sudden rise of high-entropy alloys(HEAs) has become a research hotspot in the domain of metal materials. HEAs break through the design concept of traditional single-principal element alloys, and the four core effects, especially the high entropy and cocktail effects, make HEAs exhibit much better corrosion resistance than traditional corrosion-resistant metal materials, e.g., stainless steels, copper-nickel alloys, and high-nickel alloys. Currently, the corrosion resistance of HEAs causes great concern in the field of corrosion research. This article reviews the corrosion behavior and mechanism of HEAs in various aqueous solutions, revealing the correlation among the composition, microstructure and corrosion resistance of HEAs, and elaborates the influence of heat treatment, anodizing treatment and preparation methods on the corrosion behavior of HEAs. This knowledge will benefit the on-demand design of corrosion-resistant HEAs, which is an important trend of future development. Finally, perspectives regarding the corrosion research of HEAs are outlined to guide future studies.展开更多
In this paper, a unified internal state variable(ISV) model for predicting microstructure evolution during hot working process of AZ80 magnesium alloy was developed. A novel aspect of the proposed model is that the in...In this paper, a unified internal state variable(ISV) model for predicting microstructure evolution during hot working process of AZ80 magnesium alloy was developed. A novel aspect of the proposed model is that the interactive effects of material hardening, recovery and dynamic recrystallization(DRX) on the characteristic deformation behavior were considered by incorporating the evolution laws of viscoplastic flow, dislocation activities, DRX nucleation and boundary migration in a coupled manner. The model parameters were calibrated based on the experimental data analysis and genetic algorithm(GA) based objective optimization. The predicted flow stress, DRX fraction and average grain size match well with experimental results. The proposed model was embedded in the finite element(FE) software DEFORM-3 D via user defined subroutine to simulate the hot compression and equal channel angular extrusion(ECAE) processes. The heterogeneous microstructure distributions at different deformation zones and the dislocation density evolution with competitive deformation mechanisms were captured.This study can provide a theoretical solution for the hot working problems of magnesium alloy.展开更多
High-temperature oxidation is a common failure in high-temperature environments,which widely occur in aircraft engines and aerospace thrusters;as a result,the development of anti-high-temperature oxidation materials h...High-temperature oxidation is a common failure in high-temperature environments,which widely occur in aircraft engines and aerospace thrusters;as a result,the development of anti-high-temperature oxidation materials has been pursued.Ni-based alloys are a common high-temperature material;however,they are too expensive.High-entropy alloys are alternatives for the anti-oxidation property at high temperatures because of their special structure and properties.The recent achievements of high-temperature oxidation are reviewed in this paper.The high-temperature oxidation environment,temperature,phase structure,alloy elements,and preparation methods of high-entropy alloys are summarized.The reason why high-entropy alloys have anti-oxidation ability at high temperatures is illuminated.Current research,material selection,and application prospects of high-temperature oxidation are introduced.展开更多
In this study, a new self-healing strategy that can simultaneously recover the corrosion resistance and the adhesion strength of coatings was introduced. The coating was based on a shape memory epoxy resin containing ...In this study, a new self-healing strategy that can simultaneously recover the corrosion resistance and the adhesion strength of coatings was introduced. The coating was based on a shape memory epoxy resin containing ethylene vinyl acetate(EVA) microspheres loaded with Ce(NO_(3))_(3)inhibitors, and was cured at a relatively high temperature to facilitate the fusion of adjacent microspheres for a strengthened self-healing effect. The electrochemical impedance spectroscopy(EIS) and scanning electrochemical microscopy(SECM) results demonstrated that the shape memory effect of epoxy matrix, the filling of molten EVA microspheres as well as the release of Ce(NO_(3))_(3)inhibitors contributed synergistically to suppress the corrosion reaction at the coating damage. After healing, the low frequency impedance modulus of the coatings containing Ce(NO_(3))_(3)-EVA microspheres was three orders of magnitude higher than that of the blank epoxy coating. The adhesion strength of the coatings containing Ce(NO_(3))_(3)-EVA microspheres on the metal substrate was also largely repaired thanks to the strong bonding effect of the EVA microspheres.展开更多
Recyclability and self-healing are two most critical factors in developing sustainable polymers to deal with environmental pollution and resource waste.In this work,a dynamic cross-linked polyimide insulation film wit...Recyclability and self-healing are two most critical factors in developing sustainable polymers to deal with environmental pollution and resource waste.In this work,a dynamic cross-linked polyimide insulation film with full closed-loop recyclability is successfully prepared,which also possesses good self-healing ability after being mechanical/electrical damaged depending on the Schiff base dynamic covalent bonds.The recycled and self-healed polyimide film still maintain its good tensile strength(r t)>60 MPa with Young’s modulus(E)>4 GPa,high thermal stability with glass transition temperature(T g)>220℃,and outstanding insulation property with breakdown strength(E 0)>358 kV mm^(-1),making it a very promising low energy consumption and high temperature resistant insulation material.The strategy of using Schiff base dynamic covalent bonds for reversible repairing the structure of high T g polyimides promotes the wider application of such sustainable and recyclable material in the field of electrical power and micro-electronics.展开更多
Porous Titanium scaffolds have attracted widespread attention as bone implants for avoiding the stress shielding effect and promoting bone-in-growth.In this study,multi-morphology graded scaffolds hy-bridized by Primi...Porous Titanium scaffolds have attracted widespread attention as bone implants for avoiding the stress shielding effect and promoting bone-in-growth.In this study,multi-morphology graded scaffolds hy-bridized by Primitive and Gyroid structures with porosity of 50,60,and 70%were designed(denoted as PG50,PG60,and PG70,respectively)and fabricated by selective laser melting.The simulation results showed that the maximum von-Mises stress of hybridized scaffolds increased from 504.22 to 884.24 MPa with porosity.The permeability and average pore size of multi-morphology PG50,PG60,and PG70 were in the range of 3.58×10^(-9)-5.50×10^(-9) m^(2) and 568.1-758.4μm,respectively.The microstructure of multi-morphology graded scaffolds consisted of a fully martensiticα′phase.Tested permeabilities of PG50 and PG60 were 3.27×10^(-9) and 4.35×10^(-9) m^(2),respectively,which were within the range of human bone(0.01-12.1×10^(-9) m^(2)).Elastic modulus and compressive yield strength of PG50 and PG60 ranged within 5.93^(-9).86 and 180.06-257.08 MPa,respectively.Therein,the PG50 not only exhibited a similar elastic modulus compared to human cortical bone(10.1 GPa)but also had higher strength(257.08 vs 131 MPa).The results of in vitro biocompatibility assay showed that PG50 and PG60 have better cyto-compatibility than mono-morphology scaffolds with the same porosity.Taken together,PG50 is promising to be used for the restoration of bone defects due to its excellent mechanical properties,appropriate per-meability,and good cytocompatibility.展开更多
The effect of thermoacidophilic archaeon Metallosphaera cuprina(M.cuprina)on the corrosion of Q235 carbon steel in its culture medium was investigated in this work.In the sterile culture medium,the carbon steels showe...The effect of thermoacidophilic archaeon Metallosphaera cuprina(M.cuprina)on the corrosion of Q235 carbon steel in its culture medium was investigated in this work.In the sterile culture medium,the carbon steels showed uniform corrosion morphologies and almost no corrosion products covered the sample surface during 14 days of immersion test.In the presence of M.cuprina,some corrosion pits appeared on the surface of carbon steels in the immersion test,exhibiting typical localized corrosion morphologies.Moreover,the sample surfaces were covered by a large number of insoluble precipitates during the immersion.After 14 days,the thickness of precipitates reached approximately 50μm.The results of weight loss test and electrochemical test demonstrated that the carbon steels in the M.cuprina-inoculated culture medium had higher corrosion rate than that in the sterile culture medium.The oxygen concentration cell caused by M.cuprina biofilms resulted in localized corrosion behavior,and the ferrous oxidation ability of M.cuprina accelerated the anodic dissolution of carbon steels,thus promoting the corrosion process of carbon steels.展开更多
Inflorescences are flower-bearing shoots that originate from pools of stem cells in shoot apical meristems (SAM).Inflorescence architecture is determined by a process of meristem maturation,during which stem cell fate...Inflorescences are flower-bearing shoots that originate from pools of stem cells in shoot apical meristems (SAM).Inflorescence architecture is determined by a process of meristem maturation,during which stem cell fate switches from a vegetative to a reproductive growth program.A major factor in plant reproductive success in nature and yield in agriculture is the number of branches and flowers on inflorescences (Kobayashi and Weigel,2007;展开更多
BACKGROUND Infectious diseases are still one of the greatest threats to human health,and the etiology of 20%of cases of clinical fever is unknown;therefore,rapid identification of pathogens is highly important.Traditi...BACKGROUND Infectious diseases are still one of the greatest threats to human health,and the etiology of 20%of cases of clinical fever is unknown;therefore,rapid identification of pathogens is highly important.Traditional culture methods are only able to detect a limited number of pathogens and are time-consuming;serologic detection has window periods,false-positive and false-negative problems;and nucleic acid molecular detection methods can detect several known pathogens only once.Three-generation nanopore sequencing technology provides new options for identifying pathogens.CASE SUMMARY Case 1:The patient was admitted to the hospital with abdominal pain for three days and cessation of defecation for five days,accompanied by cough and sputum.Nanopore sequencing of the drainage fluid revealed the presence of orallike bacteria,leading to a clinical diagnosis of bronchopleural fistula.Cefoperazone sodium sulbactam treatment was effective.Case 2:The patient was admitted to the hospital with fever and headache,and CT revealed lung inflammation.Antibiotic treatment for Streptococcus pneumoniae,identified through nanopore sequencing of cerebrospinal fluid,was effective.Case 3:The patient was admitted to our hospital with intermittent fever and an enlarged neck mass that had persisted for more than six months.Despite antibacterial treatment,her symptoms worsened.The nanopore sequencing results indicate that voriconazole treatment is effective for Aspergillus brookii.The patient was diagnosed with mixed cell type classical Hodgkin's lymphoma with infection.CONCLUSION Three-generation nanopore sequencing technology allows for rapid and accurate detection of pathogens in human infectious diseases.展开更多
In this work,the microbiologically influenced corrosion(MIC)of Fe_(40)(CoCrMnNi)_(60) and Fe_(60)(CoCrMnNi)_(40) medium entropy alloys(MEAs)induced by Pseudomonas aeruginosa(P.aeruginosa)was investigated.Corrosion beh...In this work,the microbiologically influenced corrosion(MIC)of Fe_(40)(CoCrMnNi)_(60) and Fe_(60)(CoCrMnNi)_(40) medium entropy alloys(MEAs)induced by Pseudomonas aeruginosa(P.aeruginosa)was investigated.Corrosion behaviors during 14 days of immersion in sterile and P.aeruginosa-inoculated culture media are presented.Under sterile conditions,both MEAs exhibited good corrosion resistance against the culture medium solution.In the presence of P.aeruginosa,the pitting corrosion of MEAs was promoted.The results of inductively coupled plasma‒mass spectrometry(ICP‒MS)and potentiodynamic polarization tests showed that the presence of P.aeruginosa promoted the selective dissolution of passive film and accelerated the corrosion of MEAs.The results of X-ray photoelectron spectroscopy(XPS)and Mott-Schottky measurements further demonstrated the degradation effect of P.aeruginosa on the passive film.Compared with Fe_(60)(CoCrMnNi)_(40),Fe_(40)(CoCrMnNi)_(60) manifested better resistance to the MIC caused by P.aeruginosa,which may be attributed to more Cr oxides and fewer Fe oxides of the passive film.展开更多
The Greenhouse Gas Monitoring Instrument(GMI)onboard the Chinese hyperspectral satellite GF5-02 can provide abundant observations of global atmospheric CO_(2),which plays an important role in climate research.CO_(2)re...The Greenhouse Gas Monitoring Instrument(GMI)onboard the Chinese hyperspectral satellite GF5-02 can provide abundant observations of global atmospheric CO_(2),which plays an important role in climate research.CO_(2)retrieval precision is the key to determining the application value of the GMI.To reduce the influence of atmospheric scattering on retrieval,we combined the Directional Polarimetric Camera(DPC)data on the same satellite to improve the anti-interference ability of GMI CO_(2)retrieval and ensure its retrieval precision.To realize the reliability and feasibility of the collaborative use of the GMI and DPC,this paper designs the pointing registration method of the GMI based on coastline observations,the spatial resolution matching method and the collaborative cloud screening method of the GMI and DPC observations.Combined with the DPC,which supplied the spectral data and aerosol product,the retrieval ability of the coupled bidirectional reflectance distribution function CO_(2)retrieval(CBCR)method developed for GMI CO_(2)retrieval was improved,with the retrieval efficiency of CO_(2)products increasing by 27%,and the CO_(2)retrieval precision increasing from 3.3 ppm to 2.7 ppm.Moreover,collaborative use not only guaranteed the GMI’s ability to detect global and area CO_(2)concentration distribution characteristics,such as significant concentration differences between the Northern and Southern Hemispheres in winter and high CO_(2)concentrations in urban agglomeration areas caused by human activities,but also extended the GMI’s potential for monitoring anomalous events,such as the Tonga volcanic eruption.展开更多
The present paper reports the synthesis of two analogs of Schzandrin C (-DDB, (-DDB with the gallic acid as the starting material. The key step is the synthesis of monomer of (-DDB and (-DDB for coupling. (-DDB, (-DD...The present paper reports the synthesis of two analogs of Schzandrin C (-DDB, (-DDB with the gallic acid as the starting material. The key step is the synthesis of monomer of (-DDB and (-DDB for coupling. (-DDB, (-DDB have different yields in Ullmann coupling reaction under the same condition. The yield of (-DDB is little lower than that of (-DDB. The AM1 calculation demonstrates that ΔH of the Ullmann coupling reaction of (-DDB and (-DDB are different. The former is -175.76966KJ/mol and the later is -203.21246KJ/mol. This is in agreement with the fact that (-DDB has higher yield than (-DDB.展开更多
The vacuum ultraviolet absorption and emission spectra of rare-gas vander Waals molecules were observed.A large broadening of at least 240Åof Xe first resonance absorption line was obtained at cell presgure 4 atm...The vacuum ultraviolet absorption and emission spectra of rare-gas vander Waals molecules were observed.A large broadening of at least 240Åof Xe first resonance absorption line was obtained at cell presgure 4 atm.Strong continuous emission of heavier rare gases at 1300-3000Åwas obtained using self-triggered condensed discharge in aπ-shaped quartz discharge tube.展开更多
The heat transfer performances of a microchannel heat sink in the presence of a nanofluid can be affected by the attachment of nanoparticle(NP)on the microchannel wall.In this study,the mechanisms underlying NP transp...The heat transfer performances of a microchannel heat sink in the presence of a nanofluid can be affected by the attachment of nanoparticle(NP)on the microchannel wall.In this study,the mechanisms underlying NP transport and attachment are comprehensively analyzed by means of a coupled double-distribution-function lattice Boltzmann model combined with lattice-gas automata.Using this approach,the temperature distribution and the two-phase flow pattern are obtained for different values of the influential parameters.The results indicate that the number of attached NPs decrease exponentially as their diameter and the fluid velocity grow.An increase in the wall temperature leads to an increase of the attached NPs,e.g.,the Al_(2)O_(3) NPs attached on the CuO microchannel wall increases by 105.8%in the range between 293 K and 343 K.There are more attached NPs in microchannels with an irregular structure.The tendency of SiO2 NP to attach to the PDMS(polydimethylsiloxane),Fe and Cu walls is less significant than that for Al_(2)O_(3) and CuO NP;Moreover,NPs detach from the PDMS microchannel wall more easily than from the Cu and Fe microchannel walls.The SiO2 attachment layer has the greatest influence on the heat transfer performance although its thickness is thinner than that for Al_(2)O_(3) and CuO NPs under the same conditions.展开更多
The Eu^3＋-Y^3＋ double-doped ZrO2 （8YSZ：Eu^3＋） phosphors with different doping concentrations of Eu^3＋ were synthesized by hydrothermal method. The dependences of the intensities of visible emission, decay lifet...The Eu^3＋-Y^3＋ double-doped ZrO2 （8YSZ：Eu^3＋） phosphors with different doping concentrations of Eu^3＋ were synthesized by hydrothermal method. The dependences of the intensities of visible emission, decay lifetimes and crystal structures on Eu^3＋ doping concentration were investigated. The optimal doping concentration of Eu^3＋ in 8YSZ：Eu^3＋ nanophosphors was determined. The morphology and crystal structure of the resulting phosphors were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and Raman spectra. The fluorescence properties of the resulting phosphors were investigated by photoluminescence spectra and decay curve. In this paper, 3 mol.% Eu^3＋ ions in 8YSZ：Eu^3＋ phosphors was the optimal doping concentration. When doping concentration was 3 tool.%, the nanophosphor had a pure tetragonal phase structure, the emission intensity was intense and decay lifetime was long, furthermore this system could be used to indicate the extent of phase transformation of thermal barrier coatings.展开更多
Inversion techniques are conducted based on the tangential x-ray crystal spectroscopy(TXCS)geometry on EAST to obtain the local profiles of ion temperature(Ti)and toroidal rotation velocity(vt).Firstly,local emissivit...Inversion techniques are conducted based on the tangential x-ray crystal spectroscopy(TXCS)geometry on EAST to obtain the local profiles of ion temperature(Ti)and toroidal rotation velocity(vt).Firstly,local emissivity profiles of the impurity argon are obtained using the asymmetrical Abel inversion.Then,the local vt and Ti profiles are calculated by considering the local emissivity profiles and the TXCS detailed geometry.In addition,how the changes in the vt profiles affect the accuracy in the Ti profiles is discussed in detail.It is also found that the lineintegrated Ti profiles are becoming less accurate with the increase in the radial gradient in the local vt profiles.Nonetheless,accurate Ti radial profiles are reconstructed after considering the effects of the emissivity and velocity,which are verified by comparing the inverted vt and Ti profiles with those local profile measurements from the Charge eXchange Recombination Spectroscopy(CXRS)on EAST.展开更多
In the frame of quantum defect theory,the state-testate dielectronic recombination rate coefficients of Fe^(25+) ion are calculated by a simple relativistic configuration interaction method.The calculated results are ...In the frame of quantum defect theory,the state-testate dielectronic recombination rate coefficients of Fe^(25+) ion are calculated by a simple relativistic configuration interaction method.The calculated results are further expressed with a two-parameter fitting formula,and then the dependence of fitting parameters on radiative decay final channel is studied.展开更多
This study aimed to explain factors affecting health-related quality of life among community-dwelling elderly individuals living in Japan. We conducted a questionnaire survey of 898 individuals at senior citizens club...This study aimed to explain factors affecting health-related quality of life among community-dwelling elderly individuals living in Japan. We conducted a questionnaire survey of 898 individuals at senior citizens clubs in a rural area near the Tokyo metropolitan area in 2015, and analyzed the responses of 715 who provided valid responses. The survey questions included basic attributes (e.g., age, economic affluence), state of health (e.g., whether s/he has heart disease or not), the Spirituality Rating Scale Related to Health in the Elderly (SP Health Scale, composed of, e.g., meaning and purpose of living, self-transcendence), the Abbreviated Lubben Social Network Scale, and the MOS 8-Item Short Form Health Survey (SF-8). Multiple regression analyses were performed using the physical component summary (PCS) and mental component summary (MCS) of the SF-8 as dependent variables and all others as independent variables. Factors associated with improved PCS were economic affluence and SP Health Scale (meaning and purpose of living), while the factors associated with reduced PCS were age and state of health (heart disease, gastrointestinal disease, osteoarthritis, lower back pain, knee pain, and eligible for long-term care). Meanwhile, factors associated with improved MCS were economic affluence, while those that were associated with reduced MCS were state of health (cancer and headache) and SP Health Scale (self-transcendence). These results suggest the need to understand spirituality in addition to the subjective economic situation, age, and medical condition of elderly individuals in order to improve their physical and mental health.展开更多
The sensitivity of cancer cells to radiation therapy varies based on cell cycle phase. Here we evaluated the differences between X-ray and carbon-ion irradiation with respect to cellular radiosensitivity and cancer cy...The sensitivity of cancer cells to radiation therapy varies based on cell cycle phase. Here we evaluated the differences between X-ray and carbon-ion irradiation with respect to cellular radiosensitivity and cancer cycle arrest in the breast cancer cell line, MCF-7. The cell survival rate, cell cycle distribution and the presence of apoptosis were measured by clonogenic assay and flow cytometry. BRCA1 and p21 protein levels were analyzed by Western blot, and the levels of human telomerase reverse transcriptase(h TERT) m RNA expression and telomere length were detected with real-time polymerase chain reaction. The results show a significant dose-dependent effects on survival rate, apoptosis and protein levels in the carbon-ion group of MCF-7 cells. Decreased proliferation was not observed at 2 Gy X-ray irradiation. There were significant differences in cellular cycle arrest, apoptosis percentages and BRCA1 and p21 protein expression between X-ray and heavy-ion groups. The results indicatedthat increasing in BRCA1 and p21 expression, and attenuation of h TERT gene expression induced by heavy-ion irradiation in MCF-7 cells might relate to mechanism of cellular radiosensitivity in G2/M arrested phase.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.52130404 and 51774039)the Project funded by China Postdoctoral Science Foundation(No.2021M690011)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(No.2021A 1515110161)the Postdoctor Research Foundation of Shunde Graduate School of University of Science and Technology Beijing(No.2021BH011)。
文摘Cemented paste backfill(CPB)has been one of the best practical approaches for tailings management and underground goaf treatment.Paste rheology is a science to study the flow and deformation behaviors of paste or filling body under the effects of stress,strain,temperature,and time during the CPB process.The goal of studying paste rheology is to solve the engineering problems existing in four key processes;that is,paste rheology should meet the engineering demands of thickening,mixing,transportation,and backfilling.However,paste rheology is extremely complicated due to its high concentration,materials complexity,and engineering characteristics of non-stratification,nonsegregation,and non-bleeding.The rheological behavior of full tailings in deep thickening,rheological behavior of paste in mixing and pipeline transportation,and rheological behavior of filling body are introduced and discussed:(1)gel point,compressive yield stress,and the hindered settling function are adopted to characterize the rheological properties of full tailings in deep thickening.Combination of Coe-Clevenger theory and Buscall-White theory can also analyze the thickening performance in the whole area of deep cone thickener;(2)yield stress and viscosity are consistent with the evolution trend of the relative structure coefficient of paste in mixing;(3)coupling effect of wall slip and time-temperature dependency has a significant influence on the rheological properties and pipeline transportation;(4)damage variable is introduced to the Burgers model to describe the creep damage of the filling body.However,in-depth and systematic studies were still needed to establish a complete theoretical system of paste rheology in metal mines.
基金the financial support from the National Key Research and Development Program of China(No.2017YFB0702100)the National Natural Science Foundation of China(No.52071014)。
文摘In the past decade, the sudden rise of high-entropy alloys(HEAs) has become a research hotspot in the domain of metal materials. HEAs break through the design concept of traditional single-principal element alloys, and the four core effects, especially the high entropy and cocktail effects, make HEAs exhibit much better corrosion resistance than traditional corrosion-resistant metal materials, e.g., stainless steels, copper-nickel alloys, and high-nickel alloys. Currently, the corrosion resistance of HEAs causes great concern in the field of corrosion research. This article reviews the corrosion behavior and mechanism of HEAs in various aqueous solutions, revealing the correlation among the composition, microstructure and corrosion resistance of HEAs, and elaborates the influence of heat treatment, anodizing treatment and preparation methods on the corrosion behavior of HEAs. This knowledge will benefit the on-demand design of corrosion-resistant HEAs, which is an important trend of future development. Finally, perspectives regarding the corrosion research of HEAs are outlined to guide future studies.
基金funding supported by National Natural Science Foundation of China(No.52175285)Beijing Municipal Natural Science Foundation(No.3182025)+1 种基金National Defense Science and Technology Rapid support Project(No.61409230113)Scientific and Technological Innovation Foundation of Shunde Graduate School,USTB and Fundamental Research Funds for the Central Universities(No.FRFBD-20-08A,FRF-TP-20-009A2)。
文摘In this paper, a unified internal state variable(ISV) model for predicting microstructure evolution during hot working process of AZ80 magnesium alloy was developed. A novel aspect of the proposed model is that the interactive effects of material hardening, recovery and dynamic recrystallization(DRX) on the characteristic deformation behavior were considered by incorporating the evolution laws of viscoplastic flow, dislocation activities, DRX nucleation and boundary migration in a coupled manner. The model parameters were calibrated based on the experimental data analysis and genetic algorithm(GA) based objective optimization. The predicted flow stress, DRX fraction and average grain size match well with experimental results. The proposed model was embedded in the finite element(FE) software DEFORM-3 D via user defined subroutine to simulate the hot compression and equal channel angular extrusion(ECAE) processes. The heterogeneous microstructure distributions at different deformation zones and the dislocation density evolution with competitive deformation mechanisms were captured.This study can provide a theoretical solution for the hot working problems of magnesium alloy.
基金This work was financially supported by the National Natural Science Foundation of China(No.52071014)the Fundamental Research Funds for the Central Universities(No.FRF-GF-19-033BZ)the National Key Research and Development Program of China(No.2020YFB0704501).
文摘High-temperature oxidation is a common failure in high-temperature environments,which widely occur in aircraft engines and aerospace thrusters;as a result,the development of anti-high-temperature oxidation materials has been pursued.Ni-based alloys are a common high-temperature material;however,they are too expensive.High-entropy alloys are alternatives for the anti-oxidation property at high temperatures because of their special structure and properties.The recent achievements of high-temperature oxidation are reviewed in this paper.The high-temperature oxidation environment,temperature,phase structure,alloy elements,and preparation methods of high-entropy alloys are summarized.The reason why high-entropy alloys have anti-oxidation ability at high temperatures is illuminated.Current research,material selection,and application prospects of high-temperature oxidation are introduced.
基金supported by the National Natural Science Foundation of China (Nos. 51771029 and 51901015)。
文摘In this study, a new self-healing strategy that can simultaneously recover the corrosion resistance and the adhesion strength of coatings was introduced. The coating was based on a shape memory epoxy resin containing ethylene vinyl acetate(EVA) microspheres loaded with Ce(NO_(3))_(3)inhibitors, and was cured at a relatively high temperature to facilitate the fusion of adjacent microspheres for a strengthened self-healing effect. The electrochemical impedance spectroscopy(EIS) and scanning electrochemical microscopy(SECM) results demonstrated that the shape memory effect of epoxy matrix, the filling of molten EVA microspheres as well as the release of Ce(NO_(3))_(3)inhibitors contributed synergistically to suppress the corrosion reaction at the coating damage. After healing, the low frequency impedance modulus of the coatings containing Ce(NO_(3))_(3)-EVA microspheres was three orders of magnitude higher than that of the blank epoxy coating. The adhesion strength of the coatings containing Ce(NO_(3))_(3)-EVA microspheres on the metal substrate was also largely repaired thanks to the strong bonding effect of the EVA microspheres.
基金This work was financially supported by the National Natural Science Foundation of China (No.51977114,52177020)Fundamental Research Funds for the Central Universities (No.FRF-NP-19-008 and FRF-TP-20-02B2)Scientific and Techno-logical Innovation Foundation of Foshan (BK21BE006).
文摘Recyclability and self-healing are two most critical factors in developing sustainable polymers to deal with environmental pollution and resource waste.In this work,a dynamic cross-linked polyimide insulation film with full closed-loop recyclability is successfully prepared,which also possesses good self-healing ability after being mechanical/electrical damaged depending on the Schiff base dynamic covalent bonds.The recycled and self-healed polyimide film still maintain its good tensile strength(r t)>60 MPa with Young’s modulus(E)>4 GPa,high thermal stability with glass transition temperature(T g)>220℃,and outstanding insulation property with breakdown strength(E 0)>358 kV mm^(-1),making it a very promising low energy consumption and high temperature resistant insulation material.The strategy of using Schiff base dynamic covalent bonds for reversible repairing the structure of high T g polyimides promotes the wider application of such sustainable and recyclable material in the field of electrical power and micro-electronics.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.51922004 and 51874037)the State Key Lab of Advanced Metals and Materials,University of Sci-ence and Technology Beijing(Nos.2020Z-04,2021Z-03,and 2022Z-12)+5 种基金the Fundamental Research Funds for the Central Universi-ties(Nos.FRF-TP-19005C1Z and 06500236)the Interdisciplinary Research Project for Young Teachers of USTB(Fundamental Re-search Funds for the Central Universities,No.FRF-IDRY-20-023)the Postdoctor Research Foundation of Shunde Graduate School of University of Science and Technology Beijing(No.2022BH001)the China Postdoctoral Science Foundation(No.2021M700377)the Guangdong Basic and Applied Basic Research Foundation(No.2021A1515110548)the State Key Laboratory of Powder Metallurgy,Central South University and the Beijing Natural Science Founda-tion(No.2212035)。
文摘Porous Titanium scaffolds have attracted widespread attention as bone implants for avoiding the stress shielding effect and promoting bone-in-growth.In this study,multi-morphology graded scaffolds hy-bridized by Primitive and Gyroid structures with porosity of 50,60,and 70%were designed(denoted as PG50,PG60,and PG70,respectively)and fabricated by selective laser melting.The simulation results showed that the maximum von-Mises stress of hybridized scaffolds increased from 504.22 to 884.24 MPa with porosity.The permeability and average pore size of multi-morphology PG50,PG60,and PG70 were in the range of 3.58×10^(-9)-5.50×10^(-9) m^(2) and 568.1-758.4μm,respectively.The microstructure of multi-morphology graded scaffolds consisted of a fully martensiticα′phase.Tested permeabilities of PG50 and PG60 were 3.27×10^(-9) and 4.35×10^(-9) m^(2),respectively,which were within the range of human bone(0.01-12.1×10^(-9) m^(2)).Elastic modulus and compressive yield strength of PG50 and PG60 ranged within 5.93^(-9).86 and 180.06-257.08 MPa,respectively.Therein,the PG50 not only exhibited a similar elastic modulus compared to human cortical bone(10.1 GPa)but also had higher strength(257.08 vs 131 MPa).The results of in vitro biocompatibility assay showed that PG50 and PG60 have better cyto-compatibility than mono-morphology scaffolds with the same porosity.Taken together,PG50 is promising to be used for the restoration of bone defects due to its excellent mechanical properties,appropriate per-meability,and good cytocompatibility.
基金supported by the National Natural Science Foundation of China(No.52001021)the China Postdoctoral Science Foundation(No.2019M660453)the Postdoctoral Research Foundation of Shunde Graduate School of University of Science and Technology Beijing(No.2020BH009)。
文摘The effect of thermoacidophilic archaeon Metallosphaera cuprina(M.cuprina)on the corrosion of Q235 carbon steel in its culture medium was investigated in this work.In the sterile culture medium,the carbon steels showed uniform corrosion morphologies and almost no corrosion products covered the sample surface during 14 days of immersion test.In the presence of M.cuprina,some corrosion pits appeared on the surface of carbon steels in the immersion test,exhibiting typical localized corrosion morphologies.Moreover,the sample surfaces were covered by a large number of insoluble precipitates during the immersion.After 14 days,the thickness of precipitates reached approximately 50μm.The results of weight loss test and electrochemical test demonstrated that the carbon steels in the M.cuprina-inoculated culture medium had higher corrosion rate than that in the sterile culture medium.The oxygen concentration cell caused by M.cuprina biofilms resulted in localized corrosion behavior,and the ferrous oxidation ability of M.cuprina accelerated the anodic dissolution of carbon steels,thus promoting the corrosion process of carbon steels.
基金supported by startup funding to C.X.from State Key Laboratory of Plant Genomics and Institute of Genetics and Developmental Biology,Chinese Academy of Sciences,and a National Science Foundation grant(IOS-1556171)to Z.B.L
文摘Inflorescences are flower-bearing shoots that originate from pools of stem cells in shoot apical meristems (SAM).Inflorescence architecture is determined by a process of meristem maturation,during which stem cell fate switches from a vegetative to a reproductive growth program.A major factor in plant reproductive success in nature and yield in agriculture is the number of branches and flowers on inflorescences (Kobayashi and Weigel,2007;
基金Supported by Research and Development Funding for Medical and Health Institutions,No.2021YL007.
文摘BACKGROUND Infectious diseases are still one of the greatest threats to human health,and the etiology of 20%of cases of clinical fever is unknown;therefore,rapid identification of pathogens is highly important.Traditional culture methods are only able to detect a limited number of pathogens and are time-consuming;serologic detection has window periods,false-positive and false-negative problems;and nucleic acid molecular detection methods can detect several known pathogens only once.Three-generation nanopore sequencing technology provides new options for identifying pathogens.CASE SUMMARY Case 1:The patient was admitted to the hospital with abdominal pain for three days and cessation of defecation for five days,accompanied by cough and sputum.Nanopore sequencing of the drainage fluid revealed the presence of orallike bacteria,leading to a clinical diagnosis of bronchopleural fistula.Cefoperazone sodium sulbactam treatment was effective.Case 2:The patient was admitted to the hospital with fever and headache,and CT revealed lung inflammation.Antibiotic treatment for Streptococcus pneumoniae,identified through nanopore sequencing of cerebrospinal fluid,was effective.Case 3:The patient was admitted to our hospital with intermittent fever and an enlarged neck mass that had persisted for more than six months.Despite antibacterial treatment,her symptoms worsened.The nanopore sequencing results indicate that voriconazole treatment is effective for Aspergillus brookii.The patient was diagnosed with mixed cell type classical Hodgkin's lymphoma with infection.CONCLUSION Three-generation nanopore sequencing technology allows for rapid and accurate detection of pathogens in human infectious diseases.
基金financially supported by the National Natural Science Foundation of China(Nos.52001021,52161160308)the China Postdoctoral Science Foundation(Nos.2021M700372 and 2021M700381)+1 种基金the Joint Fund of Basic and Applied Basic Research Fund of Guangdong Province(No.2021B1515130009)the Open Fund from State Key Laboratory of Metal Material for Marine Equipment and Application(No.SKLMEA-K202006).
文摘In this work,the microbiologically influenced corrosion(MIC)of Fe_(40)(CoCrMnNi)_(60) and Fe_(60)(CoCrMnNi)_(40) medium entropy alloys(MEAs)induced by Pseudomonas aeruginosa(P.aeruginosa)was investigated.Corrosion behaviors during 14 days of immersion in sterile and P.aeruginosa-inoculated culture media are presented.Under sterile conditions,both MEAs exhibited good corrosion resistance against the culture medium solution.In the presence of P.aeruginosa,the pitting corrosion of MEAs was promoted.The results of inductively coupled plasma‒mass spectrometry(ICP‒MS)and potentiodynamic polarization tests showed that the presence of P.aeruginosa promoted the selective dissolution of passive film and accelerated the corrosion of MEAs.The results of X-ray photoelectron spectroscopy(XPS)and Mott-Schottky measurements further demonstrated the degradation effect of P.aeruginosa on the passive film.Compared with Fe_(60)(CoCrMnNi)_(40),Fe_(40)(CoCrMnNi)_(60) manifested better resistance to the MIC caused by P.aeruginosa,which may be attributed to more Cr oxides and fewer Fe oxides of the passive film.
基金funded by National Key R&D Program of China[Grant No.2021YFE0118000]Key Research Program of the Chinese Academy of Sciences[Grant No.ZDRW-KT-2020-3]and Dragon 5 cooperation.
文摘The Greenhouse Gas Monitoring Instrument(GMI)onboard the Chinese hyperspectral satellite GF5-02 can provide abundant observations of global atmospheric CO_(2),which plays an important role in climate research.CO_(2)retrieval precision is the key to determining the application value of the GMI.To reduce the influence of atmospheric scattering on retrieval,we combined the Directional Polarimetric Camera(DPC)data on the same satellite to improve the anti-interference ability of GMI CO_(2)retrieval and ensure its retrieval precision.To realize the reliability and feasibility of the collaborative use of the GMI and DPC,this paper designs the pointing registration method of the GMI based on coastline observations,the spatial resolution matching method and the collaborative cloud screening method of the GMI and DPC observations.Combined with the DPC,which supplied the spectral data and aerosol product,the retrieval ability of the coupled bidirectional reflectance distribution function CO_(2)retrieval(CBCR)method developed for GMI CO_(2)retrieval was improved,with the retrieval efficiency of CO_(2)products increasing by 27%,and the CO_(2)retrieval precision increasing from 3.3 ppm to 2.7 ppm.Moreover,collaborative use not only guaranteed the GMI’s ability to detect global and area CO_(2)concentration distribution characteristics,such as significant concentration differences between the Northern and Southern Hemispheres in winter and high CO_(2)concentrations in urban agglomeration areas caused by human activities,but also extended the GMI’s potential for monitoring anomalous events,such as the Tonga volcanic eruption.
基金the Henan Outstanding Younth and Natural Science Foundation of China
文摘The present paper reports the synthesis of two analogs of Schzandrin C (-DDB, (-DDB with the gallic acid as the starting material. The key step is the synthesis of monomer of (-DDB and (-DDB for coupling. (-DDB, (-DDB have different yields in Ullmann coupling reaction under the same condition. The yield of (-DDB is little lower than that of (-DDB. The AM1 calculation demonstrates that ΔH of the Ullmann coupling reaction of (-DDB and (-DDB are different. The former is -175.76966KJ/mol and the later is -203.21246KJ/mol. This is in agreement with the fact that (-DDB has higher yield than (-DDB.
文摘The vacuum ultraviolet absorption and emission spectra of rare-gas vander Waals molecules were observed.A large broadening of at least 240Åof Xe first resonance absorption line was obtained at cell presgure 4 atm.Strong continuous emission of heavier rare gases at 1300-3000Åwas obtained using self-triggered condensed discharge in aπ-shaped quartz discharge tube.
基金the National Natural Science Foundation of China for financial support(No.51890894)Scientific and Technological Innovation Foundation of Shunde Graduate School,USTB(Grant No.BK19AE012).
文摘The heat transfer performances of a microchannel heat sink in the presence of a nanofluid can be affected by the attachment of nanoparticle(NP)on the microchannel wall.In this study,the mechanisms underlying NP transport and attachment are comprehensively analyzed by means of a coupled double-distribution-function lattice Boltzmann model combined with lattice-gas automata.Using this approach,the temperature distribution and the two-phase flow pattern are obtained for different values of the influential parameters.The results indicate that the number of attached NPs decrease exponentially as their diameter and the fluid velocity grow.An increase in the wall temperature leads to an increase of the attached NPs,e.g.,the Al_(2)O_(3) NPs attached on the CuO microchannel wall increases by 105.8%in the range between 293 K and 343 K.There are more attached NPs in microchannels with an irregular structure.The tendency of SiO2 NP to attach to the PDMS(polydimethylsiloxane),Fe and Cu walls is less significant than that for Al_(2)O_(3) and CuO NP;Moreover,NPs detach from the PDMS microchannel wall more easily than from the Cu and Fe microchannel walls.The SiO2 attachment layer has the greatest influence on the heat transfer performance although its thickness is thinner than that for Al_(2)O_(3) and CuO NPs under the same conditions.
基金Project supported by National Natural Science Foundation of China(21171160,21001017)the Project of Lotus Scholars Program
文摘The Eu^3＋-Y^3＋ double-doped ZrO2 （8YSZ：Eu^3＋） phosphors with different doping concentrations of Eu^3＋ were synthesized by hydrothermal method. The dependences of the intensities of visible emission, decay lifetimes and crystal structures on Eu^3＋ doping concentration were investigated. The optimal doping concentration of Eu^3＋ in 8YSZ：Eu^3＋ nanophosphors was determined. The morphology and crystal structure of the resulting phosphors were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and Raman spectra. The fluorescence properties of the resulting phosphors were investigated by photoluminescence spectra and decay curve. In this paper, 3 mol.% Eu^3＋ ions in 8YSZ：Eu^3＋ phosphors was the optimal doping concentration. When doping concentration was 3 tool.%, the nanophosphor had a pure tetragonal phase structure, the emission intensity was intense and decay lifetime was long, furthermore this system could be used to indicate the extent of phase transformation of thermal barrier coatings.
基金supported by National Natural Science Foundation of China(Nos.12175278 and 12205072)the Comprehensive Research Facility for Fusion Technology Program of China(No.2018-000052-73-01-001228)+3 种基金Major Science and Technology Infrastructure Maintenance and Reconstruction Projects of the Chinese Academy of Sciences(2021),the University Synergy Innovation Program of Anhui Province(No.GXXT-2021-029)Anhui Provincial Key Research and Development Project(No.202104a06020021)Open Fund of the Magnetic Confinement Fusion Laboratory of Anhui Province(No.2021AMF01002)the National Magnetic Confinement Fusion Science Program of China(Nos.2019YFE03040000 and 2018YFE0303103).
文摘Inversion techniques are conducted based on the tangential x-ray crystal spectroscopy(TXCS)geometry on EAST to obtain the local profiles of ion temperature(Ti)and toroidal rotation velocity(vt).Firstly,local emissivity profiles of the impurity argon are obtained using the asymmetrical Abel inversion.Then,the local vt and Ti profiles are calculated by considering the local emissivity profiles and the TXCS detailed geometry.In addition,how the changes in the vt profiles affect the accuracy in the Ti profiles is discussed in detail.It is also found that the lineintegrated Ti profiles are becoming less accurate with the increase in the radial gradient in the local vt profiles.Nonetheless,accurate Ti radial profiles are reconstructed after considering the effects of the emissivity and velocity,which are verified by comparing the inverted vt and Ti profiles with those local profile measurements from the Charge eXchange Recombination Spectroscopy(CXRS)on EAST.
基金Supported by National Natural Science Foundation of China under Grant No.19474039Natural Science Foundation of Gansu Province under Grant No.ZQ-96-02.
文摘In the frame of quantum defect theory,the state-testate dielectronic recombination rate coefficients of Fe^(25+) ion are calculated by a simple relativistic configuration interaction method.The calculated results are further expressed with a two-parameter fitting formula,and then the dependence of fitting parameters on radiative decay final channel is studied.
文摘This study aimed to explain factors affecting health-related quality of life among community-dwelling elderly individuals living in Japan. We conducted a questionnaire survey of 898 individuals at senior citizens clubs in a rural area near the Tokyo metropolitan area in 2015, and analyzed the responses of 715 who provided valid responses. The survey questions included basic attributes (e.g., age, economic affluence), state of health (e.g., whether s/he has heart disease or not), the Spirituality Rating Scale Related to Health in the Elderly (SP Health Scale, composed of, e.g., meaning and purpose of living, self-transcendence), the Abbreviated Lubben Social Network Scale, and the MOS 8-Item Short Form Health Survey (SF-8). Multiple regression analyses were performed using the physical component summary (PCS) and mental component summary (MCS) of the SF-8 as dependent variables and all others as independent variables. Factors associated with improved PCS were economic affluence and SP Health Scale (meaning and purpose of living), while the factors associated with reduced PCS were age and state of health (heart disease, gastrointestinal disease, osteoarthritis, lower back pain, knee pain, and eligible for long-term care). Meanwhile, factors associated with improved MCS were economic affluence, while those that were associated with reduced MCS were state of health (cancer and headache) and SP Health Scale (self-transcendence). These results suggest the need to understand spirituality in addition to the subjective economic situation, age, and medical condition of elderly individuals in order to improve their physical and mental health.
基金the National Natural Science Foundation of China(U1432248)Gansu Provincial Science and Technology Department(0702NKDA045)Japan Society for the Promotion of Science and National Institute of Radiological Sciences of Japan(11J364)
文摘The sensitivity of cancer cells to radiation therapy varies based on cell cycle phase. Here we evaluated the differences between X-ray and carbon-ion irradiation with respect to cellular radiosensitivity and cancer cycle arrest in the breast cancer cell line, MCF-7. The cell survival rate, cell cycle distribution and the presence of apoptosis were measured by clonogenic assay and flow cytometry. BRCA1 and p21 protein levels were analyzed by Western blot, and the levels of human telomerase reverse transcriptase(h TERT) m RNA expression and telomere length were detected with real-time polymerase chain reaction. The results show a significant dose-dependent effects on survival rate, apoptosis and protein levels in the carbon-ion group of MCF-7 cells. Decreased proliferation was not observed at 2 Gy X-ray irradiation. There were significant differences in cellular cycle arrest, apoptosis percentages and BRCA1 and p21 protein expression between X-ray and heavy-ion groups. The results indicatedthat increasing in BRCA1 and p21 expression, and attenuation of h TERT gene expression induced by heavy-ion irradiation in MCF-7 cells might relate to mechanism of cellular radiosensitivity in G2/M arrested phase.
