A novel tetraethylenepentamine(TEPA) functionalized magnetic mesoporous silica adsorbent(FNMs/TEPA) was prepared for the adsorption of Cr(Ⅲ)-ethylenediaminetetraacetic acid(EDTA)from wastewater. The characterization ...A novel tetraethylenepentamine(TEPA) functionalized magnetic mesoporous silica adsorbent(FNMs/TEPA) was prepared for the adsorption of Cr(Ⅲ)-ethylenediaminetetraacetic acid(EDTA)from wastewater. The characterization of the prepared adsorbent certified that TEPA was modified onto the magnetic mesoporous silicon(FNMs), while FNMs/TEPA maintained the ordered mesoporous and pristine magnetic properties. The batch adsorption experiments demonstrated that TEPA significantly enhanced the removal capacity of the adsorbent for Cr(Ⅲ)-EDTA. FNMs/TEPA exhibited an excellent adsorption property(13.84 mg·g-1) at p H 4.0. Even in the presence of high concentrations of coexisting ions and organic acids, the adsorption performance of FNMs/TEPA was stable. Experimental characterization and DFT demonstrated that the adsorption of Cr(Ⅲ)-EDTA was ascribed to the electrostatic interaction, hydrogen bonding, and complexation between Cr(Ⅲ)-EDTA and amino groups on the adsorbent surface. The analysis of the independent gradient model(IGM) shows that electrostatic interaction is the main mode of action in the adsorption process. Moreover, FNMs/TEPA demonstrated remarkable reusability in three regeneration cycles. These findings indicated that FNMs/TEPA possessed excellent application prospects in the disposal of wastewater containing Cr(Ⅲ)-EDTA.展开更多
The localized micro-galvanic corrosion process and the kinetic information of Mg-(7,9)Al-1Fe-x Nd alloys were investigated by in situ observation under electrochemical control and in situ atomic force microscopy(AFM)i...The localized micro-galvanic corrosion process and the kinetic information of Mg-(7,9)Al-1Fe-x Nd alloys were investigated by in situ observation under electrochemical control and in situ atomic force microscopy(AFM)in an electrolyte environment.The results revealed that the formation of the Nd-rich phase in alloys resulted in a decrease in the Volta potential difference from~400 m V(AlFe3/α-Mg)to~220 mV(Nd-rich/α-Mg),reducing the corrosion products around the cathodic phase and corrosion current density of the microscale area.The addition of Nd significantly improved the corrosion resistance,mainly due to the suppression of the micro-galvanic corrosion between the second phases and substrate.Finally,the corrosion mechanism of Mg-(7,9)Al-1Fe-x Nd alloys was discussed based on in situ observations and electrochemical results.展开更多
Revealing the localized corrosion process of Mg alloy is considered as one of the most significant ways for improving its corrosion resistance.The reliable monitor should be high distinguishability and real-time in li...Revealing the localized corrosion process of Mg alloy is considered as one of the most significant ways for improving its corrosion resistance.The reliable monitor should be high distinguishability and real-time in liquid environment.Herein,Mg-9Al-1Fe and Mg-9Al-1Fe-1Gd alloys were designed to highlight the impact of intermetallic on the corrosion behaviour.In-situ AFM with a special electrolyte circulation system and quasi-in-situ SEM observation were used to monitor the corrosion process of the designed alloys.SEM-EDS and TEM-SAED were applied to identify the intermetallic in the designed alloys,and their volta potentials were measured by SKPFM.According to the real-time and real-space in-situ AFM monitor,the corrosion process consisted of dissolution of anodicα-Mg phase,accumulation of corrosion products around cathodic phase and shedding of some fine cathodic phase.Then,the localized corrosion process of Mg alloy was revealed combined with the results of the monitor of corrosion process and Volta potential difference.展开更多
The corrosion inhibition behavior of Mg-8Li-3Al alloy in NaCl solution with sodium dodecyl sulfate(SDS)was investigated by hydrogen analysis,scanning electron microscopy(SEM),electrochemical test,scanning Kelvin probe...The corrosion inhibition behavior of Mg-8Li-3Al alloy in NaCl solution with sodium dodecyl sulfate(SDS)was investigated by hydrogen analysis,scanning electron microscopy(SEM),electrochemical test,scanning Kelvin probe force microscopy(SKPFM)and computational methods.Results showed that the corrosion resistance of Mg-8Li-3Al alloy in NaCl solution was effectively improved with SDS.The SEM and SKPFM results confirmed a dense,200 nm-thick SDS-adsorbed layer had formed on the alloy surface.The separation energy ΔE_(gap) and adsorption energy E_(ads) of SDS on the Mg surface were calculated by density functional theory and molecular dynamics simulations,respectively.And the corrosion inhibition mechanism was hypothesized and described.展开更多
In this study, we investigated the effect of the addition of Sr （0wt%, 0. lwt%, 0.2wt%, and 0.3wt%） on the microstaalcture and cor- rosion behavior of A13Ti/ADC12 composite by optical microscopy, X-ray diffraction, ...In this study, we investigated the effect of the addition of Sr （0wt%, 0. lwt%, 0.2wt%, and 0.3wt%） on the microstaalcture and cor- rosion behavior of A13Ti/ADC12 composite by optical microscopy, X-ray diffraction, sca^lning electron microscopy, mid energy diffraction spectroscopy. The results reveal that the c^-A1 phases were nearly spherical mid 40 gin in size and that the eutectic Si phases became round in the composite when the Sr content reached 0.2wt%. The A13Ti paxticles were distributed uniformly at the grain boundary. The results of the corrosion examination reveal that the A13Ti/ADC12 composite exhibited a minimum corrosion rate of 0.081 g.m 2,hl for an Sr content of 0.2wt%, which is two thirds of that of umnodified composite （0.134 g.m4.h 1）. This improved corrosion resistaalce was due to galvamc cor- rosion, which resulted from the low area ratio of the cathode to anode regions. This caused a low-density corrosion current in the composite, thereby yielding optimum corrosion resistmlce.展开更多
The microstructure,microhardness,and corrosion resistance of laser cladding Ni−WC coating on the surface of AlSi5Cu1Mg alloy were investigated by scanning electron microscopy,X-ray diffraction,microhardness testing,im...The microstructure,microhardness,and corrosion resistance of laser cladding Ni−WC coating on the surface of AlSi5Cu1Mg alloy were investigated by scanning electron microscopy,X-ray diffraction,microhardness testing,immersion corrosion testing,and electrochemical measurement.The results show that a smooth coating containing NiAl,Ni_(3)Al,M_(7)C_(3),M_(23)C_(6)phases(M=Ni,Al,Cr,W,Fe)and WC particles is prepared by laser cladding.Under a laser scanning speed of 120 mm/min,the microhardness of the cladding coating is 9−11 times that of AlSi5Cu1Mg,due to the synergistic effect of excellent metallurgical bond and newly formed carbides.The Ni−WC coating shows higher corrosion potential(−318.09 mV)and lower corrosion current density(12.33μA/cm^(2))compared with the matrix.The crack-free,dense cladding coating obviously inhibits the penetration of Cl^(−)and H^(+),leading to the remarkedly improved corrosion resistance of cladding coating.展开更多
The evolution and distribution of Al2Sm phase in as-extruded AZ61-xSm（x=0, 1.5, 2.0 and 2.5, mass fraction, %） magnesium alloys during semi-solid isothermal heat treatment were investigated. The results showed that ...The evolution and distribution of Al2Sm phase in as-extruded AZ61-xSm（x=0, 1.5, 2.0 and 2.5, mass fraction, %） magnesium alloys during semi-solid isothermal heat treatment were investigated. The results showed that when as-extruded AZ61 magnesium alloys were modified with Sm, the smaller and rounder grains were obtained during semi-solid isothermal heat treatment. When the Sm content is 2.0%（mass fraction）, the average size of the globular grains reached the smallest value of 90 μm. Although a few Al2Sm particles existed in the α-Mg grains, most of Al2Sm particles solidified at the edge of the globular grains with the width of 20 μm. These phenomena are mainly attributed to the forces acting on Al2Sm particles in front of the solid-liquid interface, leading to Al2Sm particles accumulating at the solid-liquid interface and then solidifying at the edge of the globular grains in the quenching process.展开更多
The influence of Sm （Samarium） content on microstructure and mechanical properties of recycled die-cast YLl12 aluminum alloys was investigated. The results show that many small Sm-rich particles form in the recycled...The influence of Sm （Samarium） content on microstructure and mechanical properties of recycled die-cast YLl12 aluminum alloys was investigated. The results show that many small Sm-rich particles form in the recycled die-cast YLl12 alloys with Sm addition. At the same time, the secondary dendrite arm spacing in the YLl12 alloys modified with Sm is smaller than that of the unmodified alloy. The eutectic Si of recycled die- cast YL112-xSm alloys transforms from coarse acicular morphology to fine fibres. Mechanical properties of the investigated recycled die-cast YLl12 aluminum alloys are enhanced with Sm addition, and a maximal ultimate tensile strength value （276 MPa） and elongation （3.76%） are achieved at a Sm content of 0.6wt.%. Due to the modification of eutectic Si by Sm, numerous tearing ridges and tiny dimples on the fractures of tensile samples are observed.展开更多
The phosphate protective film and micro-galvanic corrosion of biological Mg-3Zn-xNd (x = 0, 0.6, 1.2) alloys were investigated by scanning and transmission electron microscopy, quasi-in-situ observation, scanning Kelv...The phosphate protective film and micro-galvanic corrosion of biological Mg-3Zn-xNd (x = 0, 0.6, 1.2) alloys were investigated by scanning and transmission electron microscopy, quasi-in-situ observation, scanning Kelvin probe force microscopy (SKPFM) and electrochemical tests. The results revealed the Mg-Zn-Nd phases formed in Mg-3Zn alloy contained with Nd. Adding Nd resulted in a significant decline in the cracks of the phosphate protective film and micro-galvanic corrosion of alloys, which were recorded by quasi-in-situ observation. In addition, the Volta potential difference of Mg-Zn-Nd/α-Mg (~ 188 mV) was lower than MgZn/α-Mg (~ 419 mV) and Zn-rich/α-Mg (~ 260 mV), and the corrosion rates of alloys markedly decreased after the addition of 0.6 wt% Nd. The improvement in corrosion resistance of Nd-containing alloys was mainly attributed to the following: (i) the addition of Nd reduced the Volta potential difference (second phases/α-Mg);(ii) the phosphate protective film containing Nd_(2)O_(3) deposited on the surface of the alloys, effectively preventing the penetration of harmful anions.展开更多
In the link prediction task of knowledge graph completion,Graph Neural Network(GNN)-based knowledge graph completion models have been shown by previous studies to produce large improvements in prediction results.Howev...In the link prediction task of knowledge graph completion,Graph Neural Network(GNN)-based knowledge graph completion models have been shown by previous studies to produce large improvements in prediction results.However,many of the previous efforts were limited to aggregating the information given by neighboring nodes and did not take advantage of the information provided by the edges represented by relations.To address the problem,Coupling Relation Strength with Graph Convolutional Networks(RS-GCN)is proposed,which is a model with an encoder-decoder framework to realize the embedding of entities and relations in the vector space.On the encoder side,RS-GCN captures graph structure and neighborhood information while aggregating the information given by neighboring nodes.On the decoder side,RotatE is utilized to model and infer various relational patterns.The models are evaluated on standard FB15k,WN18,FB15k-237 and WN18RR datasets,and the experiments show that RS-GCN achieves better results than the current state-of-the-art classical models on the above knowledge graph datasets.展开更多
Metamorphosis is the short developmental stage characterized by dramatic ontogenetic changes that occurs in most animals.However,this important process remains largely unclear in marine invertebrates.In this study,we ...Metamorphosis is the short developmental stage characterized by dramatic ontogenetic changes that occurs in most animals.However,this important process remains largely unclear in marine invertebrates.In this study,we performed the sequential RNA sequencing of a representative mollusk,the rapa whelk(Rapana venosa),that is undergoing metamorphosis and conducted differential gene expression analysis and weighted gene co-expression network analysis(WGCNA)to investigate the overall and dynamic transcriptome responses.The results revealed that the expression of cytochrome P4502A and 3A were upregulated during metamorphosis,while the expression of H/ACA ribonucleoproteins increased 4 h after metamorphosis induction(M4 stage),indicating that R.venosa mainly responded to the pelagobenthic changes.At the M24 stage,the enrichment of V-type proton ATPase and insulin indicated the complete development of secretory organs and initiation of hormone secretion.Furthermore,at the M48 stage,the enrichment of zinc metalloproteinase and conotoxin indicated a well-developed predation system that requires exogenous nutrition.Finally,during the PL stage,the genes associated with growth control were highly enriched,implying that R.venosa had completed metamorphosis and has entered the period of rapid growth.Therefore,our study provides useful transcriptomic resources for R.venosa and contributes new insights that may assist in elucidating the mechanisms underlying metamorphosis in marine invertebrates.展开更多
RNA polymerase transcriptional pausing represents a major checkpoint in transcription in bacteria and metazoans,but it is unknown whether this phenomenon occurs in plant organelles.Here,we report that transcriptional ...RNA polymerase transcriptional pausing represents a major checkpoint in transcription in bacteria and metazoans,but it is unknown whether this phenomenon occurs in plant organelles.Here,we report that transcriptional pausing occurs in chloroplasts.We found that mTERF5 specifically and positively regulates the transcription of chloroplast psbEFLJ in Arabidopsis thaliana that encodes four key subunits of photosystem II.We found that mTERF5 causes the plastid-encoded RNA polymerase(PEP)complex to pause at psbEFLJ by binding to the+30 to+51 region of double-stranded DNA.Moreover,we revealed that mTERF5 interacts with pTAC6,an essential subunit of the PEP complex,although pTAC6 is not involved in the transcriptional pausing at psbEFLJ.We showed that mTERF5 recruits additional pTAC6 to the transcriptionally paused region of psbEFLJ,and the recruited pTAC6 proteins could be assembled into the PEP complex to regulate psbEFLJ transcription.Taken together,our findings shed light on the role of transcriptional pausing in chloroplast transcription in plants.展开更多
Flowering time(heading date)is a critical agronomic trait that determines the yield and regional adaptability of crops.Heading date 1(Hd1)is a central regulator of photoperiodic flowering in rice(Oryza sativa).However...Flowering time(heading date)is a critical agronomic trait that determines the yield and regional adaptability of crops.Heading date 1(Hd1)is a central regulator of photoperiodic flowering in rice(Oryza sativa).However,how the homeostasis of Hd1 protein is achieved is poorly understood.Here,we report that the nuclear autophagy pathway mediates Hd1 degradation in the dark to regulate flowering.Loss of autophagy function results in an accumulation of Hd1 and delays flowering under both short-day and long-day conditions.In the dark,nucleus-localized Hd1 is recognized as a substrate for autophagy and is subjected to vacuolar degradation via the autophagy protein OsATG8.The Hd1-0sATG8 interaction is required for autophagic degradation of Hd1 in the dark.Our study reveals a new mechanism by which Hd1 protein homeostasis is regulated by autophagy to control rice flowering.Our study also indicates that the regulation of flowering by autophagic degradation of Hd1 orthologs may have arisen over the course of mesangiosperm evolution,which would have increased their flexibility and adaptability to the environment by modulating flowering time.展开更多
The solidification behavior, micro structure and silicon twinning of Al-10 Si alloys with Yb addition were investigated by thermal analysis, optical microscopy, X-ray diffraction. scanning electron microscopy, and tra...The solidification behavior, micro structure and silicon twinning of Al-10 Si alloys with Yb addition were investigated by thermal analysis, optical microscopy, X-ray diffraction. scanning electron microscopy, and transmission electron microscopy. The results indicate that the nucleation temperature, minimum temperature, and growth temperature of Al-lOSi alloys decrease with increasing Yb content. The cooling curves of the Yb-modified alloys exhibit marked recalescence. The recalescence of the modified alloy peaks at 2.3 ℃ when the Yb content is 0.7 wt%. The 3 D morphologies of eutectic Si in Yb-modified alloys change from a coarse plate-like structure to a honeycomb structure with many fine fibrous structures.The Al-Si-Yb intermetallic compound is observed in the 1.0 wt% Yb-modified alloy. Meanwhile, XRD analysis and TEM results indicate that the average twin spacing in the Yb-modified alloys is 18-46.2 nm.The average twin spacing of eutectic Si decreases with increasing Yb content. When the Yb content in the modified alloy is increased to 0.7 wt%, the average twin spacing value of eutectic Si reaches to 18 nm,which promotes the formation of twins and refinement of eutectic Si.展开更多
Background:Regulatory policy(RP)is known as a major factor to improve health care system performance.A significant difference in maternal mortality rates(MMRs)was observed between New York city(NYC)and Shanghai(SH),bo...Background:Regulatory policy(RP)is known as a major factor to improve health care system performance.A significant difference in maternal mortality rates(MMRs)was observed between New York city(NYC)and Shanghai(SH),both first-class international metropolises.This study aims to adopt a quantitative evaluation model to analyze whether RP differences contribute to the different MMRs of the two cities.Methods:Based on collection of all publicly released policy documents regarding maternal health in the two cities,we assessed and compared the status of their maternal health care RPs from 2006 to 2017 through a series of quantitative indicators as regulatory elements coverage rate(RECR),departmental responsibility clarity rate(DRCR),and accountability mechanism clarity rate(AMCR),based on two characteristics of comprehensiveness and effectiveness of RPs.Pearson correlation analysis,principal component analysis,and linear regression analysis were used to test the relationships between the indicators and MMR in SH and NYC.Results:By 2017,disparities of maternal health care RP are found between SH and NYC,from the indicators of RECR(100%vs.77.0%),DRCR(38.9%vs.45.1%),and AMCR(29.2%vs.22.5%).From 2006 to 2017,RECR,DRCR,and AMCR in SH have shown a higher growth of 8.7%,53.2%,and 45.2%,compared with growth of 25.0%,12.5%,and 2.9%in NYC.The three indicators were found all negatively correlated with MMR in SH(Coefficients=-0.831,-0.833,and-0.909,and P<0.01),while only RECR and DRCR had negative correlation with MMR in NYC(Coefficients=-0.736 and-0.683,and P<0.05).Linear regression showed that the principal components of the three indicators were found with significant impact on MMRs both in SH(R=0.914,R2=0.836,P<0.001)and NYC(R=0.854,R2=0.357,P=0.04).Conclusion:Compared with NYC,the more comprehensive and effective maternal health care RPs in SH had a stronger impact on MMR control,which contributed to the differences between the two cities’MMRs to some extent.The methods and indicators we adopted for assessment are reasonable and comparable.展开更多
To data,using strong metal-support interaction(SMSI)effect to improve the catalytic performance of metal catalysts is an important strategy for heterogeneous catalysis,and this effect is basically achieved by using re...To data,using strong metal-support interaction(SMSI)effect to improve the catalytic performance of metal catalysts is an important strategy for heterogeneous catalysis,and this effect is basically achieved by using reducible metal oxides.However,the formation of SMSI between metal and inert-support has been so little coverage and remains challenge.In this work,the SMSI effect can be effectively extended to the inert support-metal catalysis system to fabricate a Cu^(0)/Cu-doped SiO_(2) catalyst with high dispersion and loading(38.5 wt.%)through the interfacial effect of inert silica.In the catalyst,subnanometric composite of Cu cluster and atomic copper(in the configuration of Cu-O-Si)can be consciously formed on the silica interface,and verified by extended X-ray absorption fine structure(EXAFS),in situ X-ray photoelectron spectroscopy(XPS),and high-angle annular dark field-scanning transmission electron microscopy(HAADF-STEM)characterization.The promoting activity in transfer-hydrogenation by the SMSI effect of Cu-silica interface and the synergistic active roles of cluster and atomic Cu have also been revealed from surface interface structure,catalytic activity,and density functional theory(DFT)theoretical calculation at an atomic level.The subnanometric composite of cluster and atomic copper species can be derived from a facile synthesis strategy of metal-inert support SMSI effect and the realistic active site of Cu-based catalyst can also been identified accurately,thus it will help to expand the application of subnanometric materials in industrial catalysis.展开更多
This work reports on a simple microfluidic strategy to controllably fabricate uniform polymeric microparticles containing hierarchical porous structures integrated with highly accessible catalytic metal organic framew...This work reports on a simple microfluidic strategy to controllably fabricate uniform polymeric microparticles containing hierarchical porous structures integrated with highly accessible catalytic metal organic frameworks for efficient degradation of organic contaminants.Monodisperse(W1/O)/W2 emulsion droplets generated from microfluidics are used as templates for the microparticle synthesis.The emulsion droplets contain tiny water microdroplets from homogenization and water nanodroplets from diffusion-induced swollen micelles as the dual pore-forming templates,and Fe-based metal-organic framework nanorods as the nanocatalysts.The obtained microparticles possess interconnected hierarchical porous structures decorated with highly accessible Fe-based metal-organic framework nanorods for enhanced degradation of organic contaminants via a heterogeneous Fenton-like reaction.Such a degradation performance is highlighted by using these microparticles for efficient degradation of rhodamine B in hydrogen peroxide solution.This work provides a simple and general strategy to flexibly combine hierarchical porous structures and catalytic metal-organic frameworks to engineer advanced microparticles for water decontamination.展开更多
Advanced characterization techniques are utilized to investigate the effect of laser surface treatment on microstructural evolution of pure titanium（Ti）.The results show that there are three distinctly different typ...Advanced characterization techniques are utilized to investigate the effect of laser surface treatment on microstructural evolution of pure titanium（Ti）.The results show that there are three distinctly different types of microstructure from surface to substrate in Ti samples,including phase transformation and solidification microstructure in zone I（melting zone）;insufficient recrystallization grains with residual a martensitic plates in zone II（heat-affected zone,HAZ）;fully recrystallization microstructure in zone III（base metal,BM）.The hardness evolution profiles under different laser treatment parameters are similar.The highest hardness in MZ is ascribed to α plate,while the lowest hardness value in HAZ is due to the insufficiently recrystallized grains.The metallurgical process on the laser-modified Ti samples is systematically discussed in this work.展开更多
We present a sufficient and necessary condition for the subshift of finite type to be a measure-preserving transformation or to be a strong mixing measure-preserving transformation with respect to the Hausdorff measur...We present a sufficient and necessary condition for the subshift of finite type to be a measure-preserving transformation or to be a strong mixing measure-preserving transformation with respect to the Hausdorff measure. It is proved that a strong mixing subshift of finite type has a chaotic set with full Hausdorff measure.展开更多
基金supported by the National Natural Science Foundation of China(22076111)Key Research and Development Program of Shaanxi(2024GX-YBXM-427),China.
文摘A novel tetraethylenepentamine(TEPA) functionalized magnetic mesoporous silica adsorbent(FNMs/TEPA) was prepared for the adsorption of Cr(Ⅲ)-ethylenediaminetetraacetic acid(EDTA)from wastewater. The characterization of the prepared adsorbent certified that TEPA was modified onto the magnetic mesoporous silicon(FNMs), while FNMs/TEPA maintained the ordered mesoporous and pristine magnetic properties. The batch adsorption experiments demonstrated that TEPA significantly enhanced the removal capacity of the adsorbent for Cr(Ⅲ)-EDTA. FNMs/TEPA exhibited an excellent adsorption property(13.84 mg·g-1) at p H 4.0. Even in the presence of high concentrations of coexisting ions and organic acids, the adsorption performance of FNMs/TEPA was stable. Experimental characterization and DFT demonstrated that the adsorption of Cr(Ⅲ)-EDTA was ascribed to the electrostatic interaction, hydrogen bonding, and complexation between Cr(Ⅲ)-EDTA and amino groups on the adsorbent surface. The analysis of the independent gradient model(IGM) shows that electrostatic interaction is the main mode of action in the adsorption process. Moreover, FNMs/TEPA demonstrated remarkable reusability in three regeneration cycles. These findings indicated that FNMs/TEPA possessed excellent application prospects in the disposal of wastewater containing Cr(Ⅲ)-EDTA.
基金financial support from the National Natural Science Foundation of China(No.51961026)。
文摘The localized micro-galvanic corrosion process and the kinetic information of Mg-(7,9)Al-1Fe-x Nd alloys were investigated by in situ observation under electrochemical control and in situ atomic force microscopy(AFM)in an electrolyte environment.The results revealed that the formation of the Nd-rich phase in alloys resulted in a decrease in the Volta potential difference from~400 m V(AlFe3/α-Mg)to~220 mV(Nd-rich/α-Mg),reducing the corrosion products around the cathodic phase and corrosion current density of the microscale area.The addition of Nd significantly improved the corrosion resistance,mainly due to the suppression of the micro-galvanic corrosion between the second phases and substrate.Finally,the corrosion mechanism of Mg-(7,9)Al-1Fe-x Nd alloys was discussed based on in situ observations and electrochemical results.
基金support by the National Natural Science Foundation of China(51961026)the Interdisciplinary Innovation Fund of Nanchang University(Project No.2019-9166-27060003).
文摘Revealing the localized corrosion process of Mg alloy is considered as one of the most significant ways for improving its corrosion resistance.The reliable monitor should be high distinguishability and real-time in liquid environment.Herein,Mg-9Al-1Fe and Mg-9Al-1Fe-1Gd alloys were designed to highlight the impact of intermetallic on the corrosion behaviour.In-situ AFM with a special electrolyte circulation system and quasi-in-situ SEM observation were used to monitor the corrosion process of the designed alloys.SEM-EDS and TEM-SAED were applied to identify the intermetallic in the designed alloys,and their volta potentials were measured by SKPFM.According to the real-time and real-space in-situ AFM monitor,the corrosion process consisted of dissolution of anodicα-Mg phase,accumulation of corrosion products around cathodic phase and shedding of some fine cathodic phase.Then,the localized corrosion process of Mg alloy was revealed combined with the results of the monitor of corrosion process and Volta potential difference.
基金the financial support by the National Natural Science Foundation of China(51961026)the Interdisciplinary Innovation Fund of Nanchang University(Project No.2019-9166-27060003)。
文摘The corrosion inhibition behavior of Mg-8Li-3Al alloy in NaCl solution with sodium dodecyl sulfate(SDS)was investigated by hydrogen analysis,scanning electron microscopy(SEM),electrochemical test,scanning Kelvin probe force microscopy(SKPFM)and computational methods.Results showed that the corrosion resistance of Mg-8Li-3Al alloy in NaCl solution was effectively improved with SDS.The SEM and SKPFM results confirmed a dense,200 nm-thick SDS-adsorbed layer had formed on the alloy surface.The separation energy ΔE_(gap) and adsorption energy E_(ads) of SDS on the Mg surface were calculated by density functional theory and molecular dynamics simulations,respectively.And the corrosion inhibition mechanism was hypothesized and described.
基金financially supported by the National Natural Science Foundation of China(No.51364035)the Natural Science Foundation of Jiangxi Province(No.20171BAB206034)
文摘In this study, we investigated the effect of the addition of Sr （0wt%, 0. lwt%, 0.2wt%, and 0.3wt%） on the microstaalcture and cor- rosion behavior of A13Ti/ADC12 composite by optical microscopy, X-ray diffraction, sca^lning electron microscopy, mid energy diffraction spectroscopy. The results reveal that the c^-A1 phases were nearly spherical mid 40 gin in size and that the eutectic Si phases became round in the composite when the Sr content reached 0.2wt%. The A13Ti paxticles were distributed uniformly at the grain boundary. The results of the corrosion examination reveal that the A13Ti/ADC12 composite exhibited a minimum corrosion rate of 0.081 g.m 2,hl for an Sr content of 0.2wt%, which is two thirds of that of umnodified composite （0.134 g.m4.h 1）. This improved corrosion resistaalce was due to galvamc cor- rosion, which resulted from the low area ratio of the cathode to anode regions. This caused a low-density corrosion current in the composite, thereby yielding optimum corrosion resistmlce.
文摘The microstructure,microhardness,and corrosion resistance of laser cladding Ni−WC coating on the surface of AlSi5Cu1Mg alloy were investigated by scanning electron microscopy,X-ray diffraction,microhardness testing,immersion corrosion testing,and electrochemical measurement.The results show that a smooth coating containing NiAl,Ni_(3)Al,M_(7)C_(3),M_(23)C_(6)phases(M=Ni,Al,Cr,W,Fe)and WC particles is prepared by laser cladding.Under a laser scanning speed of 120 mm/min,the microhardness of the cladding coating is 9−11 times that of AlSi5Cu1Mg,due to the synergistic effect of excellent metallurgical bond and newly formed carbides.The Ni−WC coating shows higher corrosion potential(−318.09 mV)and lower corrosion current density(12.33μA/cm^(2))compared with the matrix.The crack-free,dense cladding coating obviously inhibits the penetration of Cl^(−)and H^(+),leading to the remarkedly improved corrosion resistance of cladding coating.
基金Project(51405216) supported by the National Natural Science Foundation of ChinaProject(20153BCB23023) supported by the Training Programme Foundation for Young Scientists of Jiangxi Province,China
文摘The evolution and distribution of Al2Sm phase in as-extruded AZ61-xSm（x=0, 1.5, 2.0 and 2.5, mass fraction, %） magnesium alloys during semi-solid isothermal heat treatment were investigated. The results showed that when as-extruded AZ61 magnesium alloys were modified with Sm, the smaller and rounder grains were obtained during semi-solid isothermal heat treatment. When the Sm content is 2.0%（mass fraction）, the average size of the globular grains reached the smallest value of 90 μm. Although a few Al2Sm particles existed in the α-Mg grains, most of Al2Sm particles solidified at the edge of the globular grains with the width of 20 μm. These phenomena are mainly attributed to the forces acting on Al2Sm particles in front of the solid-liquid interface, leading to Al2Sm particles accumulating at the solid-liquid interface and then solidifying at the edge of the globular grains in the quenching process.
基金supported by the National Natural Science Foundation of China(51405216,51165032)Jiangxi Province Education Commission Foundation(GJJ14200)
文摘The influence of Sm （Samarium） content on microstructure and mechanical properties of recycled die-cast YLl12 aluminum alloys was investigated. The results show that many small Sm-rich particles form in the recycled die-cast YLl12 alloys with Sm addition. At the same time, the secondary dendrite arm spacing in the YLl12 alloys modified with Sm is smaller than that of the unmodified alloy. The eutectic Si of recycled die- cast YL112-xSm alloys transforms from coarse acicular morphology to fine fibres. Mechanical properties of the investigated recycled die-cast YLl12 aluminum alloys are enhanced with Sm addition, and a maximal ultimate tensile strength value （276 MPa） and elongation （3.76%） are achieved at a Sm content of 0.6wt.%. Due to the modification of eutectic Si by Sm, numerous tearing ridges and tiny dimples on the fractures of tensile samples are observed.
基金support by the National Natural Science Foundation of China(No.51961026).
文摘The phosphate protective film and micro-galvanic corrosion of biological Mg-3Zn-xNd (x = 0, 0.6, 1.2) alloys were investigated by scanning and transmission electron microscopy, quasi-in-situ observation, scanning Kelvin probe force microscopy (SKPFM) and electrochemical tests. The results revealed the Mg-Zn-Nd phases formed in Mg-3Zn alloy contained with Nd. Adding Nd resulted in a significant decline in the cracks of the phosphate protective film and micro-galvanic corrosion of alloys, which were recorded by quasi-in-situ observation. In addition, the Volta potential difference of Mg-Zn-Nd/α-Mg (~ 188 mV) was lower than MgZn/α-Mg (~ 419 mV) and Zn-rich/α-Mg (~ 260 mV), and the corrosion rates of alloys markedly decreased after the addition of 0.6 wt% Nd. The improvement in corrosion resistance of Nd-containing alloys was mainly attributed to the following: (i) the addition of Nd reduced the Volta potential difference (second phases/α-Mg);(ii) the phosphate protective film containing Nd_(2)O_(3) deposited on the surface of the alloys, effectively preventing the penetration of harmful anions.
文摘In the link prediction task of knowledge graph completion,Graph Neural Network(GNN)-based knowledge graph completion models have been shown by previous studies to produce large improvements in prediction results.However,many of the previous efforts were limited to aggregating the information given by neighboring nodes and did not take advantage of the information provided by the edges represented by relations.To address the problem,Coupling Relation Strength with Graph Convolutional Networks(RS-GCN)is proposed,which is a model with an encoder-decoder framework to realize the embedding of entities and relations in the vector space.On the encoder side,RS-GCN captures graph structure and neighborhood information while aggregating the information given by neighboring nodes.On the decoder side,RotatE is utilized to model and infer various relational patterns.The models are evaluated on standard FB15k,WN18,FB15k-237 and WN18RR datasets,and the experiments show that RS-GCN achieves better results than the current state-of-the-art classical models on the above knowledge graph datasets.
基金supported by the National Natural Science Foundation of China(Grant Nos.32002409,31972814,32002374)the Natural Science Foundation of Shandong Province(Grant No.ZR2019BD003)+6 种基金the China Postdoctoral Science Foundation(Grant No.2021M703248)Young Elite Scientists Sponsorship Program by CAST,2021QNRC001earmarked fund for the Modern Agro-industry Technology Research System(CARS-49)the Major Scientific and Technological Innovation Project of Shandong Provincial Key Research and Development Program(2019JZZY020708)the Industry Leading Talents Project of Taishan Scholars(Recipient:Tao Zhang)the“Double Hundred”Blue Industry Leader Team of Yantai(Recipient:Tao Zhang)the Creative Team Project of the Laboratory for Marine Ecology and Environmental Science,Qingdao National Laboratory for Marine Science and Technology(no.LMEESCTSP-2018-1).
文摘Metamorphosis is the short developmental stage characterized by dramatic ontogenetic changes that occurs in most animals.However,this important process remains largely unclear in marine invertebrates.In this study,we performed the sequential RNA sequencing of a representative mollusk,the rapa whelk(Rapana venosa),that is undergoing metamorphosis and conducted differential gene expression analysis and weighted gene co-expression network analysis(WGCNA)to investigate the overall and dynamic transcriptome responses.The results revealed that the expression of cytochrome P4502A and 3A were upregulated during metamorphosis,while the expression of H/ACA ribonucleoproteins increased 4 h after metamorphosis induction(M4 stage),indicating that R.venosa mainly responded to the pelagobenthic changes.At the M24 stage,the enrichment of V-type proton ATPase and insulin indicated the complete development of secretory organs and initiation of hormone secretion.Furthermore,at the M48 stage,the enrichment of zinc metalloproteinase and conotoxin indicated a well-developed predation system that requires exogenous nutrition.Finally,during the PL stage,the genes associated with growth control were highly enriched,implying that R.venosa had completed metamorphosis and has entered the period of rapid growth.Therefore,our study provides useful transcriptomic resources for R.venosa and contributes new insights that may assist in elucidating the mechanisms underlying metamorphosis in marine invertebrates.
基金the National Natural Science Foundation of China(reference number 31730102)the State Key Basic Research and Development Plan of China(reference number 2015CB150105)+2 种基金the Key Research Plan of Frontier Sciences of the Chinese Academy of Sciences(reference number QYZDJ-SSW-SMC003)the Strategic Priority Research Program of the Chinese Academy of Sciences(reference number XDB17030100)the National Key Scientific Instrument and Equipment Development Project of China(grant no.2013YQ030595).
文摘RNA polymerase transcriptional pausing represents a major checkpoint in transcription in bacteria and metazoans,but it is unknown whether this phenomenon occurs in plant organelles.Here,we report that transcriptional pausing occurs in chloroplasts.We found that mTERF5 specifically and positively regulates the transcription of chloroplast psbEFLJ in Arabidopsis thaliana that encodes four key subunits of photosystem II.We found that mTERF5 causes the plastid-encoded RNA polymerase(PEP)complex to pause at psbEFLJ by binding to the+30 to+51 region of double-stranded DNA.Moreover,we revealed that mTERF5 interacts with pTAC6,an essential subunit of the PEP complex,although pTAC6 is not involved in the transcriptional pausing at psbEFLJ.We showed that mTERF5 recruits additional pTAC6 to the transcriptionally paused region of psbEFLJ,and the recruited pTAC6 proteins could be assembled into the PEP complex to regulate psbEFLJ transcription.Taken together,our findings shed light on the role of transcriptional pausing in chloroplast transcription in plants.
基金supported by the National Key Research and Development Program of China(2020YFA0907602)the National Natural Science Foundation of China(31730102).
文摘Flowering time(heading date)is a critical agronomic trait that determines the yield and regional adaptability of crops.Heading date 1(Hd1)is a central regulator of photoperiodic flowering in rice(Oryza sativa).However,how the homeostasis of Hd1 protein is achieved is poorly understood.Here,we report that the nuclear autophagy pathway mediates Hd1 degradation in the dark to regulate flowering.Loss of autophagy function results in an accumulation of Hd1 and delays flowering under both short-day and long-day conditions.In the dark,nucleus-localized Hd1 is recognized as a substrate for autophagy and is subjected to vacuolar degradation via the autophagy protein OsATG8.The Hd1-0sATG8 interaction is required for autophagic degradation of Hd1 in the dark.Our study reveals a new mechanism by which Hd1 protein homeostasis is regulated by autophagy to control rice flowering.Our study also indicates that the regulation of flowering by autophagic degradation of Hd1 orthologs may have arisen over the course of mesangiosperm evolution,which would have increased their flexibility and adaptability to the environment by modulating flowering time.
基金supported by the National Natural Science Foundation of China(51405216)the Training Programme Foundation for Young Scientists of Jiangxi Province(20153BCB23023)the Natural Science Foundation of Jiangxi Province(20171BAB206005)
文摘The solidification behavior, micro structure and silicon twinning of Al-10 Si alloys with Yb addition were investigated by thermal analysis, optical microscopy, X-ray diffraction. scanning electron microscopy, and transmission electron microscopy. The results indicate that the nucleation temperature, minimum temperature, and growth temperature of Al-lOSi alloys decrease with increasing Yb content. The cooling curves of the Yb-modified alloys exhibit marked recalescence. The recalescence of the modified alloy peaks at 2.3 ℃ when the Yb content is 0.7 wt%. The 3 D morphologies of eutectic Si in Yb-modified alloys change from a coarse plate-like structure to a honeycomb structure with many fine fibrous structures.The Al-Si-Yb intermetallic compound is observed in the 1.0 wt% Yb-modified alloy. Meanwhile, XRD analysis and TEM results indicate that the average twin spacing in the Yb-modified alloys is 18-46.2 nm.The average twin spacing of eutectic Si decreases with increasing Yb content. When the Yb content in the modified alloy is increased to 0.7 wt%, the average twin spacing value of eutectic Si reaches to 18 nm,which promotes the formation of twins and refinement of eutectic Si.
基金funded by the Three-Year Action Plan of Shanghai Municipality Strengthens Public Health System Construction 2015-2017(No.GWIV-32)the National Natural Science Foundation Project(No.71774031)and the Health-related Major Social Risk Early Warning Collaborative Innovation Center Research Fund,a Sub-project of the National"Twelfth Five-Year"Science and Technology Support(No.2014BAI08B01).
文摘Background:Regulatory policy(RP)is known as a major factor to improve health care system performance.A significant difference in maternal mortality rates(MMRs)was observed between New York city(NYC)and Shanghai(SH),both first-class international metropolises.This study aims to adopt a quantitative evaluation model to analyze whether RP differences contribute to the different MMRs of the two cities.Methods:Based on collection of all publicly released policy documents regarding maternal health in the two cities,we assessed and compared the status of their maternal health care RPs from 2006 to 2017 through a series of quantitative indicators as regulatory elements coverage rate(RECR),departmental responsibility clarity rate(DRCR),and accountability mechanism clarity rate(AMCR),based on two characteristics of comprehensiveness and effectiveness of RPs.Pearson correlation analysis,principal component analysis,and linear regression analysis were used to test the relationships between the indicators and MMR in SH and NYC.Results:By 2017,disparities of maternal health care RP are found between SH and NYC,from the indicators of RECR(100%vs.77.0%),DRCR(38.9%vs.45.1%),and AMCR(29.2%vs.22.5%).From 2006 to 2017,RECR,DRCR,and AMCR in SH have shown a higher growth of 8.7%,53.2%,and 45.2%,compared with growth of 25.0%,12.5%,and 2.9%in NYC.The three indicators were found all negatively correlated with MMR in SH(Coefficients=-0.831,-0.833,and-0.909,and P<0.01),while only RECR and DRCR had negative correlation with MMR in NYC(Coefficients=-0.736 and-0.683,and P<0.05).Linear regression showed that the principal components of the three indicators were found with significant impact on MMRs both in SH(R=0.914,R2=0.836,P<0.001)and NYC(R=0.854,R2=0.357,P=0.04).Conclusion:Compared with NYC,the more comprehensive and effective maternal health care RPs in SH had a stronger impact on MMR control,which contributed to the differences between the two cities’MMRs to some extent.The methods and indicators we adopted for assessment are reasonable and comparable.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.52072371,51871209,and 51502297)key technologies research and development program of Anhui province(No.006153430011)instrument developing project of the Chinese Academy of Sciences(No.yz201421).
文摘To data,using strong metal-support interaction(SMSI)effect to improve the catalytic performance of metal catalysts is an important strategy for heterogeneous catalysis,and this effect is basically achieved by using reducible metal oxides.However,the formation of SMSI between metal and inert-support has been so little coverage and remains challenge.In this work,the SMSI effect can be effectively extended to the inert support-metal catalysis system to fabricate a Cu^(0)/Cu-doped SiO_(2) catalyst with high dispersion and loading(38.5 wt.%)through the interfacial effect of inert silica.In the catalyst,subnanometric composite of Cu cluster and atomic copper(in the configuration of Cu-O-Si)can be consciously formed on the silica interface,and verified by extended X-ray absorption fine structure(EXAFS),in situ X-ray photoelectron spectroscopy(XPS),and high-angle annular dark field-scanning transmission electron microscopy(HAADF-STEM)characterization.The promoting activity in transfer-hydrogenation by the SMSI effect of Cu-silica interface and the synergistic active roles of cluster and atomic Cu have also been revealed from surface interface structure,catalytic activity,and density functional theory(DFT)theoretical calculation at an atomic level.The subnanometric composite of cluster and atomic copper species can be derived from a facile synthesis strategy of metal-inert support SMSI effect and the realistic active site of Cu-based catalyst can also been identified accurately,thus it will help to expand the application of subnanometric materials in industrial catalysis.
基金the National Natural Science Foundation of China(Grant Nos.21922809,22108186,and 21991101)the Sichuan Science and Technology Program(Grant No.2019YJ0528).
文摘This work reports on a simple microfluidic strategy to controllably fabricate uniform polymeric microparticles containing hierarchical porous structures integrated with highly accessible catalytic metal organic frameworks for efficient degradation of organic contaminants.Monodisperse(W1/O)/W2 emulsion droplets generated from microfluidics are used as templates for the microparticle synthesis.The emulsion droplets contain tiny water microdroplets from homogenization and water nanodroplets from diffusion-induced swollen micelles as the dual pore-forming templates,and Fe-based metal-organic framework nanorods as the nanocatalysts.The obtained microparticles possess interconnected hierarchical porous structures decorated with highly accessible Fe-based metal-organic framework nanorods for enhanced degradation of organic contaminants via a heterogeneous Fenton-like reaction.Such a degradation performance is highlighted by using these microparticles for efficient degradation of rhodamine B in hydrogen peroxide solution.This work provides a simple and general strategy to flexibly combine hierarchical porous structures and catalytic metal-organic frameworks to engineer advanced microparticles for water decontamination.
基金supported by the National Natural Science Foundation of China (Nos. 51401039 and 51501026)the Natural Science Foundation of Chongqing (No. CSTC2014jcyj A50017)the Scientific and Technological Research Program of Chongqing Municipal Education Commission (Nos. KJ1500923 and KJ1709204)
文摘Advanced characterization techniques are utilized to investigate the effect of laser surface treatment on microstructural evolution of pure titanium（Ti）.The results show that there are three distinctly different types of microstructure from surface to substrate in Ti samples,including phase transformation and solidification microstructure in zone I（melting zone）;insufficient recrystallization grains with residual a martensitic plates in zone II（heat-affected zone,HAZ）;fully recrystallization microstructure in zone III（base metal,BM）.The hardness evolution profiles under different laser treatment parameters are similar.The highest hardness in MZ is ascribed to α plate,while the lowest hardness value in HAZ is due to the insufficiently recrystallized grains.The metallurgical process on the laser-modified Ti samples is systematically discussed in this work.
基金Supported by National Natural Science Foundation of China （Grant No. 60763009）
文摘We present a sufficient and necessary condition for the subshift of finite type to be a measure-preserving transformation or to be a strong mixing measure-preserving transformation with respect to the Hausdorff measure. It is proved that a strong mixing subshift of finite type has a chaotic set with full Hausdorff measure.
