This study was aimed to analyze the effect of procyanidin B2(PC)and tannin acid(TA)on the activities of cholesterol esterase(CEase)and the inhibitory mechanisms of enzymatic activity.The interaction mechanisms were in...This study was aimed to analyze the effect of procyanidin B2(PC)and tannin acid(TA)on the activities of cholesterol esterase(CEase)and the inhibitory mechanisms of enzymatic activity.The interaction mechanisms were investigated by enzymatic kinetics,multi-spectroscopy methods,thermodynamics analysis,molecular docking,and dynamic simulations.PC and TA could bind with CEase and inhibit the activity of enzyme in a mixed-competitive manner and non-competitive manner,which was verified by molecular docking simulations and dynamics simulations.Also,PC and TA showed the synergistic inhibition with orlistat.Fluorescence,UVvis and the thermodynamic analysis revealed that the complexes were formed from CEase and inhibitors by noncovalent interaction.As revealed by the circular dichroism results,both PC and TA decreased enzymatic activities by altering the conformations of CEase.The inhibition of PC and TA on CEase might be one mechanism for its cholesterol-lowering effect.展开更多
We investigated the asymmetric tension-compression(T-C)behavior of ZA21 bars with bimodal and uniform structures through axial tension and compression tests.The results show that the yield strengths of bars having bim...We investigated the asymmetric tension-compression(T-C)behavior of ZA21 bars with bimodal and uniform structures through axial tension and compression tests.The results show that the yield strengths of bars having bimodal structure are 206.42 and 140.28 MPa under tension and compression,respectively,which are higher than those of bars having uniform structure with tensile and compressive yield strength of 183.71 and 102.86 MPa,respectively.Prismatic slip and extension twinning under tension and basal slip and extension twinning under compression dominate the yield behavior and induce the T-C asymmetry.However,due to the basal slip activated in fine grains under tension and the inhibition of extension twinning by fine grains under compression,the bimodal structure possesses a lower T-C asymmetry(0.68)compared to the uniform structure(0.56).Multiple extension twins occur during deformation,and the selection of twin variants depends on the Schmid factor of the six variants activated by parent grains.Furthermore,the strengthening effect of the bimodal structure depends on the grain size and the ratio of coarse and fine grains.展开更多
Magnesium(Mg)is the fourth most abundant element in the human body and is important in terms of specific osteogenesis functions.Here,we provide a comprehensive review of the use of magnesium-based biomaterials(MBs)in ...Magnesium(Mg)is the fourth most abundant element in the human body and is important in terms of specific osteogenesis functions.Here,we provide a comprehensive review of the use of magnesium-based biomaterials(MBs)in bone reconstruction.We review the history of MBs and their excellent biocompatibility,biodegradability and osteopromotive properties,highlighting them as candidates for a new generation of biodegradable orthopedic implants.In particular,the results reported in the field-specific literature(280 articles)in recent decades are dissected with respect to the extensive variety of MBs for orthopedic applications,including Mg/Mg alloys,bioglasses,bioceramics,and polymer materials.We also summarize the osteogenic mechanism of MBs,including a detailed section on the physiological process,namely,the enhanced osteogenesis,promotion of osteoblast adhesion and motility,immunomodulation,and enhanced angiogenesis.Moreover,the merits and limitations of current bone grafts and substitutes are compared.The objective of this review is to reveal the strong potential of MBs for their use as agents in bone repair and regeneration and to highlight issues that impede their clinical translation.Finally,the development and challenges of MBs for transplanted orthopedic materials are discussed.展开更多
The effect of Gd,Ce and Y elements on texture,recrystallization and mechanical properties of Mg–1.5Zn alloys was investigated.The results show that the addition of Gd,Ce and Y elements in Mg–1.5Zn alloy,which rolled...The effect of Gd,Ce and Y elements on texture,recrystallization and mechanical properties of Mg–1.5Zn alloys was investigated.The results show that the addition of Gd,Ce and Y elements in Mg–1.5Zn alloy,which rolled at 450℃ and subsequently annealed at 350℃ for 1h,can effectively weaken and modify the basal texture,characterized by the splitting basal pole toward to transverse direction,leading to the yield and tensile strength,the highest along the rolling direction and the lowest along the transverse direction.Besides,the unique basal texture contributes to the significant improvement of elongation at room temperature.Electron back scattering diffraction(EBSD)analysis indicated that the non-basal texture in Mg–1.5Zn–0.2RE alloys can be attributed to obstructive effect of static recrystallization and the non-basal orientation grains nucleation near pre-existing grain boundaries during annealing.Specially,the Mg–1.5Zn–0.2Gd sheet exhibits much excellent plasticity with the elongation of 27%than Mg–1.5Zn–0.2Ce and Mg–1.5Zn–0.2Y alloys,resulting from the less and smaller second phase of MgZnGd.展开更多
The formability of magnesium alloys at ambient temperature can be enhanced by alloying additions such as Ca and RE elements,which is ascribed to the weakened basal texture.To produce magnesium alloy sheets with excell...The formability of magnesium alloys at ambient temperature can be enhanced by alloying additions such as Ca and RE elements,which is ascribed to the weakened basal texture.To produce magnesium alloy sheets with excellent comprehensive performance,the evolution of texture characterization during fabrication process and subsequent effect of texture on mechanical properties are vital controlling factors.In this investigation,three experimental Mg-3Al series alloys were hot rolled and annealed to sheets with 1 mm thickness.The microstructure evolution during rolling and annealing process was investigated.Furthermore,the influence of texture on tensile properties along different tensile directions was also studied.The results show that weakened basal texture and refined grains were achieved with the co-addition of Ca and RE element.However,strengthening of mechanical properties wasn't obtained.During hot rolling process,microstructure was refined,second phase particles broken,and basal texture was increased.While basal texture was weakened during annealing process.Recrystallization behavior influenced by formation of second phase was dominated to attenuate basal texture.Tensile deformation behavior was controlled by basal slip and followed Schmid factor criterion.Moreover,the weakened basal texture and activation of non-basal slips during hot rolling process can contribute to diminish the anisotropy of tensile properties.展开更多
The morphology, structure, and chemical composition of precipitates in the final microstructure of Nb-V-Ti microalloyed X70 acicular ferrite pipeline steel were investigated using transmission electron microscopy （TE...The morphology, structure, and chemical composition of precipitates in the final microstructure of Nb-V-Ti microalloyed X70 acicular ferrite pipeline steel were investigated using transmission electron microscopy （TEM） and energy dispersive X-ray spectroscopy （EDS）. Precipitates observed by TEM can be classified into two groups. The large precipitates are complex compounds that comprise square-shaped TiN precipitate as core with fine Nb-containing precipitate nucleated on pre-existing TiN precipitate as caps on one or more faces at high temperature. In contrast, the fine and spherical Nb carbides and/or carbonitrides precipitate heterogeneously on dislocations and sub-boundaries at low temperature. From the analysis in terms of thermodynamics, EDS and chemical cornposition of the steel, NbC precipitation is considered to be the predominant precipitation behavior in the tested steel under the processing conditions of this research.展开更多
As one of the most attractive non-radiative power transfer mechanisms without cables,efficient magnetic resonance wireless power transfer(WPT)in the near field has been extensively developed in recent years,and promot...As one of the most attractive non-radiative power transfer mechanisms without cables,efficient magnetic resonance wireless power transfer(WPT)in the near field has been extensively developed in recent years,and promoted a variety of practical applications,such as mobile phones,medical implant devices and electric vehicles.However,the physical mechanism behind some key limitations of the resonance WPT,such as frequency splitting and size-dependent efficiency,is not very clear under the widely used circuit model.Here,we review the recently developed efficient and stable resonance WPT based on non-Hermitian physics,which starts from a completely different avenue(utilizing loss and gain)to introduce novel functionalities to the resonance WPT.From the perspective of non-Hermitian photonics,the coherent and incoherent effects compete and coexist in the WPT system,and the weak stable of energy transfer mainly comes from the broken phase associated with the phase transition of parity-time symmetry.Based on this basic physical framework,some optimization schemes are proposed,including using nonlinear effect,using bound states in the continuum,or resorting to the system with high-order parity-time symmetry.Moreover,the combination of non-Hermitian physics and topological photonics in multi-coil system also provides a versatile platform for long-range robust WPT with topological protection.Therefore,the non-Hermitian physics can not only exactly predict the main results of current WPT systems,but also provide new ways to solve the difficulties of previous designs.展开更多
The limited wide applicability of commercial Mg alloys is mainly attributed to the poor corrosion resistance.Addition of alloying elements is the simplest and effective method to improve the corrosion properties.Based...The limited wide applicability of commercial Mg alloys is mainly attributed to the poor corrosion resistance.Addition of alloying elements is the simplest and effective method to improve the corrosion properties.Based on the low-cost alloy composition design,the corro-sion behavior of commercial Mg-3Al-1Zn(AZ31)alloy bearing minor Ca or Sn element was characterized by scanning Kelvin probe force microscopy,hydrogen evolution,electrochemical measurements,and corrosion morphology analysis.Results revealed that the potential differ-ence of Al_(2)Ca/α-Mg and Mg_(2)Sn/α-Mg was(230±19)mV and(80±6)mV,respectively,much lower than that of Al_(8)Mn_(5)/α-Mg(430±31)mV in AZ31 alloy,which illustrated that AZ31-0.2Sn alloy performed the best corrosion resistance,followed by AZ31-0.2Ca,while AZ31 al-loy exhibited the worst corrosion resistance.Moreover,Sn dissolved into matrix obviously increased the potential ofα-Mg and participated in the formation of dense SnO_(2) film at the interface of matrix,while Ca element was enriched in the corrosion product layer,resulting in the cor-rosion product layer of AZ31-0.2Ca/Sn alloys more compact,stable,and protective than AZ31 alloy.Therefore,AZ31 alloy bearing 0.2wt%Ca or Sn element exhibited excellent balanced properties,which is potential to be applied in commercial more comprehensively.展开更多
Administration of chicory polysaccharides(CP) can modify lipid metabolism, improve dyslipidemia, and reduce liver inflammation, all of which may help alleviate non-alcoholic fatty liver disease(NAFLD). However, the un...Administration of chicory polysaccharides(CP) can modify lipid metabolism, improve dyslipidemia, and reduce liver inflammation, all of which may help alleviate non-alcoholic fatty liver disease(NAFLD). However, the underlying mechanisms remain unclear. This study aimed to gain further understanding of the potential molecular mechanisms that mediate the protective effects of CP against NAFLD via transcriptomic and metabolomic analyses. Hepatic RNA-sequencing analysis demonstrated that long-term intake of CP restored expression of lipid metabolism-related genes Xbp1, Insig2, and Cth in NAFLD rats, thereby inhibiting de novo lipogenesis. Moreover, CP consumption restored expression levels of genes involved in pro-inflammatory responses, such as Irf1. In addition, metabolic data confirmed that CP treatment increased levels of L-palmitoylcarnitine and hexadecanoyl-Co A, implying that CP administration can promote hepatic fatty acid β-oxidation. The present results demonstrate the underlying mechanisms of CP in high-fat dietinduced NAFLD rats and suggest that CP treatment might provide a dietary therapeutic tool for the treatment of NAFLD in humans.展开更多
In the present study, cultured human SHG-44 glioma cells were subjected to a hypoxic environment simulated using the CoOl2 method. Flow cytometry showed increased reactive oxygen species production in these cells. Rea...In the present study, cultured human SHG-44 glioma cells were subjected to a hypoxic environment simulated using the CoOl2 method. Flow cytometry showed increased reactive oxygen species production in these cells. Real-time reverse transcription-PCR showed significantly increased hypoxia-inducible factor-la mRNA expression in cells exposed to the hypoxic condition. The antioxidant N-acetylcysteine significantly inhibited reactive oxygen species production and reduced hypoxia-inducible factor-la mRNA expression in normoxic and hypoxic groups, especially in the latter group. These findings indicate that hypoxia induces reactive oxygen species production and hypoxia-inducible factor-la mRNA expression in human SHG-44 glioma cells, and that the antioxidant N-acetylcysteine can inhibit these changes.展开更多
A rat model of extra-vertebral foramen cervical nerve entrapment was established according to the following parameters： stimulation intensity 20 V; frequency 50 Hz; pulse width 200 μs; duration 333 ms/s for a total ...A rat model of extra-vertebral foramen cervical nerve entrapment was established according to the following parameters： stimulation intensity 20 V; frequency 50 Hz; pulse width 200 μs; duration 333 ms/s for a total of 8 hours. After the electrical stimulation, rats exhibited mild muscle fiber atrophy, mild inflammatory exudates, connective tissue local fibrosis and chondrocyte metaplasia. Mean muscle fiber cross-sectional area was reduced. The nerve myelin sheath continuity was partially demyelinated. The microstructure of nerve cells was disrupted and these symptoms worsened with prolongation of the stimulation. The shoulder, neck and upper extremity muscles on the tested side demonstrated positive sharp waves and fibrillations. The severity increased with continuation of the stimulation. High amplitude and polyphasic motor unit potentials gradually appeared. Similar findings were seen in the contralateral side, but at a less severe level.展开更多
The purpose of this study was to develop poly(amidoamine)(PAMAM)-functionalized multi-walled carbon nanotubes(MWNTs)loaded with a poorly water-soluble drug,intended to improve the drug-loading capacity,dissolution an...The purpose of this study was to develop poly(amidoamine)(PAMAM)-functionalized multi-walled carbon nanotubes(MWNTs)loaded with a poorly water-soluble drug,intended to improve the drug-loading capacity,dissolution and design a sustained release system.MWNTs were modified with a carboxyl group by acid treatment and then complex with PAMAM.PAMAM-MWNTs were investigated as a scaffold for loading the model drug,Carvedilol(CAR),using three different methods(the fusion method,the incipient wetness impregnation method,and the solvent method).The effects of different pore size,specific surface area and physical state were systematically studied using FT-IR,TGA,SEM,DSC,nitrogen adsorption,XPS and XRD.All the samples made by PAMAM-MWNTs to load the drug had a marked effect on the drug-loading capacity as well as drug dissolution,especially theⅡ-30%.展开更多
The microstructure of a cold-deformed Al-4Cu-Mg alloy during semi-solid treatment was investigated, which shows that grain detachment and grain spheroidization processes during the semi-solid treatment are very import...The microstructure of a cold-deformed Al-4Cu-Mg alloy during semi-solid treatment was investigated, which shows that grain detachment and grain spheroidization processes during the semi-solid treatment are very important to control the fabricated semi-solid microstructures. For the two different processes, the driving force comes from the external heat source and the reduction in total interfacial area, respectively. The evolution models of microstructure morphology in the two processes were presented based on microstructure observations. It can be found that these models are useful to provide a reasonable estimated critical time of the evolution of microstructure during the semi-solid treatment.展开更多
The power infrastructure of the power system is massive in size and dispersed throughout the system.Therefore,how to protect the information security in the operation and maintenance of power equipment is a difficult ...The power infrastructure of the power system is massive in size and dispersed throughout the system.Therefore,how to protect the information security in the operation and maintenance of power equipment is a difficult problem.This paper proposes an improved time-stamped blockchain technology biometric fuzzy feature for electrical equipment maintenance.Compared with previous blockchain transactions,the time-stamped fuzzy biometric signature proposed in this paper overcomes the difficulty that the key is easy to be stolen by hackers and can protect the security of information during operation and maintenance.Finally,the effectiveness of the proposed method is verified by experiments.展开更多
In order to study the effects of Eucalyptus mixed plantation with different mixed tree species and mixed proportion on soil nutrient accumulation and fertility quality, Eucalyptus-Mytilaria laosensis and Eucalyptus-Ma...In order to study the effects of Eucalyptus mixed plantation with different mixed tree species and mixed proportion on soil nutrient accumulation and fertility quality, Eucalyptus-Mytilaria laosensis and Eucalyptus-Magnolia sumatrana mixed plantations in Guangxi State-owned Qipo Forest Farm were selected as the research objects. Based on 15 conventional soil fertility indexes, the minimum data set and membership function method were used to evaluate the soil fertility quality of mixed plantations with different structures. The results showed that compared with pure forest, the soil organic matter, total nitrogen, total potassium, alkali hydrolyzable nitrogen, available phosphorus, available potassium and other nutrients of mixed plantations with different treatments were significantly increased, and the contents of Cu and Zn in trace elements were most significantly increased. Compared with pure forest, the soil fertility quality of mixed plantations with different structures was significantly improved. The treatment with the highest soil fertility quality was 25% of Eucalyptus-M. sumatrana mixed plantation. When formulating production and management strategies, it can refer to construction measures of the mixed plantation to ensure the sustainability of forest soil fertility, and promote the healthy and sustainable development of Eucalyptus plantation and downstream industries in Guangxi.展开更多
With the increasing requirement of a higher living quality and the growing awareness of energy saving, how to improve the indoor comfort level and to reduce the expenditure of energy and slow down the rate of natural ...With the increasing requirement of a higher living quality and the growing awareness of energy saving, how to improve the indoor comfort level and to reduce the expenditure of energy and slow down the rate of natural resource consumption is becoming increasingly important. The theory of open-plan housing is able to provide a more flexible and adaptive space for the users and bring sustainable and economic benefit in the way of making full use of construction materials. Sustainable architecture design, as a method to respond the phenomenon, is able to low down the building＇ s energy consumption and has enormous potentials in creation of sustainable living environment and a high-quality dwelling condition. The primary aim of this research is to create a new sustainable architecture design method for occupancy by integrating openplan housing theory and application of sustainable technologies. Numerical simulation by computer program is applied in order to investigate and evaluate the possibility of this method in teruas of improving indoor comfort level and energy-saving capacity.展开更多
Bound states in the continuum(BICs)in artificial photonic structures have received considerable attention since they offer unique methods for the extreme field localization and enhancement of light-matter interactions...Bound states in the continuum(BICs)in artificial photonic structures have received considerable attention since they offer unique methods for the extreme field localization and enhancement of light-matter interactions.Usually,the symmetry-protected BICs are located at high symmetric points,while the positions of accidental BICs achieved by tuning the parameters will appear at some points in momentum space.Up to now,to accurately design the position of the accidental BIC in momentum space is still a challenge.Here,we theoretically and experimentally demonstrate an accurately designed accidental BIC in a two-coupled-oscillator system consisting of bilayer gratings,where the optical response of each grating can be described by a single resonator model.By changing the interlayer distance between the gratings to tune the propagation phase shift related to wave vectors,the position of the accidental BIC can be arbitrarily controlled in momentum space.Moreover,we present a general method and rigorous numerical analyses for extracting the polarization vector fields to observe the topological properties of BICs from the polarization-resolved transmission spectra.Finally,an application of the highly efficient second harmonic generation assisted by quasi-BIC is demonstrated.Our work provides a straightforward strategy for manipulating BICs and studying their topological properties in momentum space.展开更多
Metasurfaces with spin-selective transmission play an increasingly critical role in realizing optical chiral responses,especially for strong intrinsic chirality,which is limited to complex three-dimensional geometry.I...Metasurfaces with spin-selective transmission play an increasingly critical role in realizing optical chiral responses,especially for strong intrinsic chirality,which is limited to complex three-dimensional geometry.In this paper,we propose a planar metasurface capable of generating maximal intrinsic chirality and achieving dual-band spinselective transmission utilizing dual quasi-bound states in the continuum(quasi-BICs)caused by the structural symmetry breaking.Interestingly,the value of circular dichroism(CD)and the transmittance of two kinds of circular polarization states can be arbitrarily controlled by tuning the asymmetry parameter.Remarkable CD approaching unity with the maximum transmittance up to 0.95 is experimentally achieved in the dual band.Furthermore,assisted by chiral BICs,the application in polarization multiplexed near-field image display is also exhibited.Our work provides a new avenue to flexibly control intrinsic chirality in planar structure and offers an alternative strategy to develop chiral sensing,multiband spin-selective transmission,and high-performance circularly polarized wave detection.The basic principle and design method of our experiments in the microwave regime can be extended to other bands,such as the terahertz and infrared wavelengths.展开更多
基金supported by the National Basic Research Program of China(‘973’program,2013CB127106)。
文摘This study was aimed to analyze the effect of procyanidin B2(PC)and tannin acid(TA)on the activities of cholesterol esterase(CEase)and the inhibitory mechanisms of enzymatic activity.The interaction mechanisms were investigated by enzymatic kinetics,multi-spectroscopy methods,thermodynamics analysis,molecular docking,and dynamic simulations.PC and TA could bind with CEase and inhibit the activity of enzyme in a mixed-competitive manner and non-competitive manner,which was verified by molecular docking simulations and dynamics simulations.Also,PC and TA showed the synergistic inhibition with orlistat.Fluorescence,UVvis and the thermodynamic analysis revealed that the complexes were formed from CEase and inhibitors by noncovalent interaction.As revealed by the circular dichroism results,both PC and TA decreased enzymatic activities by altering the conformations of CEase.The inhibition of PC and TA on CEase might be one mechanism for its cholesterol-lowering effect.
基金financially supported by the National Natural Science Foundation of China (No. 52275305)the Fundamental Research Funds for the Central Universities (No. FRF-IC-20-10)the China Postdoctoral Science Foundation (No. 2021M700378)
文摘We investigated the asymmetric tension-compression(T-C)behavior of ZA21 bars with bimodal and uniform structures through axial tension and compression tests.The results show that the yield strengths of bars having bimodal structure are 206.42 and 140.28 MPa under tension and compression,respectively,which are higher than those of bars having uniform structure with tensile and compressive yield strength of 183.71 and 102.86 MPa,respectively.Prismatic slip and extension twinning under tension and basal slip and extension twinning under compression dominate the yield behavior and induce the T-C asymmetry.However,due to the basal slip activated in fine grains under tension and the inhibition of extension twinning by fine grains under compression,the bimodal structure possesses a lower T-C asymmetry(0.68)compared to the uniform structure(0.56).Multiple extension twins occur during deformation,and the selection of twin variants depends on the Schmid factor of the six variants activated by parent grains.Furthermore,the strengthening effect of the bimodal structure depends on the grain size and the ratio of coarse and fine grains.
基金financial support from the National Natural Science Foundation of China(No.81672230)the Natural Science Foundation of Chongqing(No.cstc2020jcyjmsxm2234)+1 种基金the Top-notch Young Talent Project of Chongqing Traditional Chinese Medicine Hospital(No.CQSZYY2020008)the Chongqing Graduate Research Innovation Project(No.CYS20199)。
文摘Magnesium(Mg)is the fourth most abundant element in the human body and is important in terms of specific osteogenesis functions.Here,we provide a comprehensive review of the use of magnesium-based biomaterials(MBs)in bone reconstruction.We review the history of MBs and their excellent biocompatibility,biodegradability and osteopromotive properties,highlighting them as candidates for a new generation of biodegradable orthopedic implants.In particular,the results reported in the field-specific literature(280 articles)in recent decades are dissected with respect to the extensive variety of MBs for orthopedic applications,including Mg/Mg alloys,bioglasses,bioceramics,and polymer materials.We also summarize the osteogenic mechanism of MBs,including a detailed section on the physiological process,namely,the enhanced osteogenesis,promotion of osteoblast adhesion and motility,immunomodulation,and enhanced angiogenesis.Moreover,the merits and limitations of current bone grafts and substitutes are compared.The objective of this review is to reveal the strong potential of MBs for their use as agents in bone repair and regeneration and to highlight issues that impede their clinical translation.Finally,the development and challenges of MBs for transplanted orthopedic materials are discussed.
文摘The effect of Gd,Ce and Y elements on texture,recrystallization and mechanical properties of Mg–1.5Zn alloys was investigated.The results show that the addition of Gd,Ce and Y elements in Mg–1.5Zn alloy,which rolled at 450℃ and subsequently annealed at 350℃ for 1h,can effectively weaken and modify the basal texture,characterized by the splitting basal pole toward to transverse direction,leading to the yield and tensile strength,the highest along the rolling direction and the lowest along the transverse direction.Besides,the unique basal texture contributes to the significant improvement of elongation at room temperature.Electron back scattering diffraction(EBSD)analysis indicated that the non-basal texture in Mg–1.5Zn–0.2RE alloys can be attributed to obstructive effect of static recrystallization and the non-basal orientation grains nucleation near pre-existing grain boundaries during annealing.Specially,the Mg–1.5Zn–0.2Gd sheet exhibits much excellent plasticity with the elongation of 27%than Mg–1.5Zn–0.2Ce and Mg–1.5Zn–0.2Y alloys,resulting from the less and smaller second phase of MgZnGd.
基金The authors would like to thank the financial support of Fundamental Research Funds for the Central Universities(No.2302019FRF-IC-19-018)Aviation Science Foundation Project(No.20181174001).
文摘The formability of magnesium alloys at ambient temperature can be enhanced by alloying additions such as Ca and RE elements,which is ascribed to the weakened basal texture.To produce magnesium alloy sheets with excellent comprehensive performance,the evolution of texture characterization during fabrication process and subsequent effect of texture on mechanical properties are vital controlling factors.In this investigation,three experimental Mg-3Al series alloys were hot rolled and annealed to sheets with 1 mm thickness.The microstructure evolution during rolling and annealing process was investigated.Furthermore,the influence of texture on tensile properties along different tensile directions was also studied.The results show that weakened basal texture and refined grains were achieved with the co-addition of Ca and RE element.However,strengthening of mechanical properties wasn't obtained.During hot rolling process,microstructure was refined,second phase particles broken,and basal texture was increased.While basal texture was weakened during annealing process.Recrystallization behavior influenced by formation of second phase was dominated to attenuate basal texture.Tensile deformation behavior was controlled by basal slip and followed Schmid factor criterion.Moreover,the weakened basal texture and activation of non-basal slips during hot rolling process can contribute to diminish the anisotropy of tensile properties.
文摘The morphology, structure, and chemical composition of precipitates in the final microstructure of Nb-V-Ti microalloyed X70 acicular ferrite pipeline steel were investigated using transmission electron microscopy （TEM） and energy dispersive X-ray spectroscopy （EDS）. Precipitates observed by TEM can be classified into two groups. The large precipitates are complex compounds that comprise square-shaped TiN precipitate as core with fine Nb-containing precipitate nucleated on pre-existing TiN precipitate as caps on one or more faces at high temperature. In contrast, the fine and spherical Nb carbides and/or carbonitrides precipitate heterogeneously on dislocations and sub-boundaries at low temperature. From the analysis in terms of thermodynamics, EDS and chemical cornposition of the steel, NbC precipitation is considered to be the predominant precipitation behavior in the tested steel under the processing conditions of this research.
基金supported by the National Key Research and Development Program of China (Grant No. 2016YFA0301101)the National Natural Science Foundation of China (Grant Nos. 91850206, 61621001, 2004284, 11674247, and 11974261)+3 种基金Shanghai Science and Technology Committee, China (Grant Nos. 18JC1410900 and 18ZR1442900)the China Postdoctoral Science Foundation (Grant Nos. 2019TQ0232 and 2019M661605)the Shanghai Super Postdoctoral Incentive ProgramFundamental Research Funds for the Central Universities, China
文摘As one of the most attractive non-radiative power transfer mechanisms without cables,efficient magnetic resonance wireless power transfer(WPT)in the near field has been extensively developed in recent years,and promoted a variety of practical applications,such as mobile phones,medical implant devices and electric vehicles.However,the physical mechanism behind some key limitations of the resonance WPT,such as frequency splitting and size-dependent efficiency,is not very clear under the widely used circuit model.Here,we review the recently developed efficient and stable resonance WPT based on non-Hermitian physics,which starts from a completely different avenue(utilizing loss and gain)to introduce novel functionalities to the resonance WPT.From the perspective of non-Hermitian photonics,the coherent and incoherent effects compete and coexist in the WPT system,and the weak stable of energy transfer mainly comes from the broken phase associated with the phase transition of parity-time symmetry.Based on this basic physical framework,some optimization schemes are proposed,including using nonlinear effect,using bound states in the continuum,or resorting to the system with high-order parity-time symmetry.Moreover,the combination of non-Hermitian physics and topological photonics in multi-coil system also provides a versatile platform for long-range robust WPT with topological protection.Therefore,the non-Hermitian physics can not only exactly predict the main results of current WPT systems,but also provide new ways to solve the difficulties of previous designs.
基金This work is financially supported by the Fundamental Research Funds for the Central Universities,China(Nos.2302017FRF-IC-17-001,2302018FRF-IC-18-004,232019 FRF-IC-19-018,and 2302020FRF-IC-20-10)the China Postdoctoral Science Foundation(No.2021M700378).
文摘The limited wide applicability of commercial Mg alloys is mainly attributed to the poor corrosion resistance.Addition of alloying elements is the simplest and effective method to improve the corrosion properties.Based on the low-cost alloy composition design,the corro-sion behavior of commercial Mg-3Al-1Zn(AZ31)alloy bearing minor Ca or Sn element was characterized by scanning Kelvin probe force microscopy,hydrogen evolution,electrochemical measurements,and corrosion morphology analysis.Results revealed that the potential differ-ence of Al_(2)Ca/α-Mg and Mg_(2)Sn/α-Mg was(230±19)mV and(80±6)mV,respectively,much lower than that of Al_(8)Mn_(5)/α-Mg(430±31)mV in AZ31 alloy,which illustrated that AZ31-0.2Sn alloy performed the best corrosion resistance,followed by AZ31-0.2Ca,while AZ31 al-loy exhibited the worst corrosion resistance.Moreover,Sn dissolved into matrix obviously increased the potential ofα-Mg and participated in the formation of dense SnO_(2) film at the interface of matrix,while Ca element was enriched in the corrosion product layer,resulting in the cor-rosion product layer of AZ31-0.2Ca/Sn alloys more compact,stable,and protective than AZ31 alloy.Therefore,AZ31 alloy bearing 0.2wt%Ca or Sn element exhibited excellent balanced properties,which is potential to be applied in commercial more comprehensively.
基金supported by the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (18KJD18000220KJA416003+5 种基金20KJA41600318KJA180007)the Key Subject of Ecology of Jiangsu Province (SUJIAOYANHAN[2022]No.2)Excellent Scientific and Technological Innovation Team of Colleges and Universities of Jiangsu Province (SUJIAOKE[2021]No.1)the Key Subject of Biology of Nanjing (NINGJIAOGAOSHI[2021] No.16)the Youth program of Nanjing Xiaozhuang University (2019NXY47)。
文摘Administration of chicory polysaccharides(CP) can modify lipid metabolism, improve dyslipidemia, and reduce liver inflammation, all of which may help alleviate non-alcoholic fatty liver disease(NAFLD). However, the underlying mechanisms remain unclear. This study aimed to gain further understanding of the potential molecular mechanisms that mediate the protective effects of CP against NAFLD via transcriptomic and metabolomic analyses. Hepatic RNA-sequencing analysis demonstrated that long-term intake of CP restored expression of lipid metabolism-related genes Xbp1, Insig2, and Cth in NAFLD rats, thereby inhibiting de novo lipogenesis. Moreover, CP consumption restored expression levels of genes involved in pro-inflammatory responses, such as Irf1. In addition, metabolic data confirmed that CP treatment increased levels of L-palmitoylcarnitine and hexadecanoyl-Co A, implying that CP administration can promote hepatic fatty acid β-oxidation. The present results demonstrate the underlying mechanisms of CP in high-fat dietinduced NAFLD rats and suggest that CP treatment might provide a dietary therapeutic tool for the treatment of NAFLD in humans.
文摘In the present study, cultured human SHG-44 glioma cells were subjected to a hypoxic environment simulated using the CoOl2 method. Flow cytometry showed increased reactive oxygen species production in these cells. Real-time reverse transcription-PCR showed significantly increased hypoxia-inducible factor-la mRNA expression in cells exposed to the hypoxic condition. The antioxidant N-acetylcysteine significantly inhibited reactive oxygen species production and reduced hypoxia-inducible factor-la mRNA expression in normoxic and hypoxic groups, especially in the latter group. These findings indicate that hypoxia induces reactive oxygen species production and hypoxia-inducible factor-la mRNA expression in human SHG-44 glioma cells, and that the antioxidant N-acetylcysteine can inhibit these changes.
基金the National Natural Science Foundation of China,No. 81171707the Major State Basic Research Program of China,No.2012CB933600+2 种基金Shanghai Pujiang Program,No.11PJD016China Postdoctoral Science Foundation,No. 20090460629Fund for Key Disciplines of Shanghai Municipal Education Commission,No.J50206
文摘A rat model of extra-vertebral foramen cervical nerve entrapment was established according to the following parameters： stimulation intensity 20 V; frequency 50 Hz; pulse width 200 μs; duration 333 ms/s for a total of 8 hours. After the electrical stimulation, rats exhibited mild muscle fiber atrophy, mild inflammatory exudates, connective tissue local fibrosis and chondrocyte metaplasia. Mean muscle fiber cross-sectional area was reduced. The nerve myelin sheath continuity was partially demyelinated. The microstructure of nerve cells was disrupted and these symptoms worsened with prolongation of the stimulation. The shoulder, neck and upper extremity muscles on the tested side demonstrated positive sharp waves and fibrillations. The severity increased with continuation of the stimulation. High amplitude and polyphasic motor unit potentials gradually appeared. Similar findings were seen in the contralateral side, but at a less severe level.
基金the National Basic Research Program of China(973 Program)(No.2009CB930300)National Natural Science Foundation of China(No.81273449).
文摘The purpose of this study was to develop poly(amidoamine)(PAMAM)-functionalized multi-walled carbon nanotubes(MWNTs)loaded with a poorly water-soluble drug,intended to improve the drug-loading capacity,dissolution and design a sustained release system.MWNTs were modified with a carboxyl group by acid treatment and then complex with PAMAM.PAMAM-MWNTs were investigated as a scaffold for loading the model drug,Carvedilol(CAR),using three different methods(the fusion method,the incipient wetness impregnation method,and the solvent method).The effects of different pore size,specific surface area and physical state were systematically studied using FT-IR,TGA,SEM,DSC,nitrogen adsorption,XPS and XRD.All the samples made by PAMAM-MWNTs to load the drug had a marked effect on the drug-loading capacity as well as drug dissolution,especially theⅡ-30%.
基金This work was financially supported by the Doctorate Creation Foundation of Northwestern Polytechnical University (No.200210)
文摘The microstructure of a cold-deformed Al-4Cu-Mg alloy during semi-solid treatment was investigated, which shows that grain detachment and grain spheroidization processes during the semi-solid treatment are very important to control the fabricated semi-solid microstructures. For the two different processes, the driving force comes from the external heat source and the reduction in total interfacial area, respectively. The evolution models of microstructure morphology in the two processes were presented based on microstructure observations. It can be found that these models are useful to provide a reasonable estimated critical time of the evolution of microstructure during the semi-solid treatment.
基金This research was funded by science and technology project of State Grid JiangSu Electric Power Co.,Ltd.(Research on Key Technologies of power network security digital identity authentication and management and control based on blockchain,Grant No.is J2021021).
文摘The power infrastructure of the power system is massive in size and dispersed throughout the system.Therefore,how to protect the information security in the operation and maintenance of power equipment is a difficult problem.This paper proposes an improved time-stamped blockchain technology biometric fuzzy feature for electrical equipment maintenance.Compared with previous blockchain transactions,the time-stamped fuzzy biometric signature proposed in this paper overcomes the difficulty that the key is easy to be stolen by hackers and can protect the security of information during operation and maintenance.Finally,the effectiveness of the proposed method is verified by experiments.
基金Supported by Guangxi Forestry Science and Technology Promotion Demonstration Project (GUILINKEYAN[2021]23, GUILINKEYAN[2021]6)。
文摘In order to study the effects of Eucalyptus mixed plantation with different mixed tree species and mixed proportion on soil nutrient accumulation and fertility quality, Eucalyptus-Mytilaria laosensis and Eucalyptus-Magnolia sumatrana mixed plantations in Guangxi State-owned Qipo Forest Farm were selected as the research objects. Based on 15 conventional soil fertility indexes, the minimum data set and membership function method were used to evaluate the soil fertility quality of mixed plantations with different structures. The results showed that compared with pure forest, the soil organic matter, total nitrogen, total potassium, alkali hydrolyzable nitrogen, available phosphorus, available potassium and other nutrients of mixed plantations with different treatments were significantly increased, and the contents of Cu and Zn in trace elements were most significantly increased. Compared with pure forest, the soil fertility quality of mixed plantations with different structures was significantly improved. The treatment with the highest soil fertility quality was 25% of Eucalyptus-M. sumatrana mixed plantation. When formulating production and management strategies, it can refer to construction measures of the mixed plantation to ensure the sustainability of forest soil fertility, and promote the healthy and sustainable development of Eucalyptus plantation and downstream industries in Guangxi.
文摘With the increasing requirement of a higher living quality and the growing awareness of energy saving, how to improve the indoor comfort level and to reduce the expenditure of energy and slow down the rate of natural resource consumption is becoming increasingly important. The theory of open-plan housing is able to provide a more flexible and adaptive space for the users and bring sustainable and economic benefit in the way of making full use of construction materials. Sustainable architecture design, as a method to respond the phenomenon, is able to low down the building＇ s energy consumption and has enormous potentials in creation of sustainable living environment and a high-quality dwelling condition. The primary aim of this research is to create a new sustainable architecture design method for occupancy by integrating openplan housing theory and application of sustainable technologies. Numerical simulation by computer program is applied in order to investigate and evaluate the possibility of this method in teruas of improving indoor comfort level and energy-saving capacity.
基金supported by the Science and Technology Major Project of Fujian Province,China (2022HZ027006)Fujian Provincial Science and Technology Planning Project (2022I0006)+1 种基金Quanzhou Municipal Science and Technology Major Project,China (2022GZ7)the National Natural Science Foundation of China (62274036)。
基金National Key Research and Development Program of China(2021YFA1400602,2021YFA1400603,2022YFA1404800)National Natural Science Foundation of China(12274325,12234007,12221004,12004284,11974261,91850206)+2 种基金Major Program of National Natural Science Foundation of China(91963212)Science and Technology Commission of Shanghai Municipality(22142200400,21DZ1101500,2019SHZDZX01)Basic and Applied Basic Research Foundation of Guangdong Province(2023A1515011024)。
文摘Bound states in the continuum(BICs)in artificial photonic structures have received considerable attention since they offer unique methods for the extreme field localization and enhancement of light-matter interactions.Usually,the symmetry-protected BICs are located at high symmetric points,while the positions of accidental BICs achieved by tuning the parameters will appear at some points in momentum space.Up to now,to accurately design the position of the accidental BIC in momentum space is still a challenge.Here,we theoretically and experimentally demonstrate an accurately designed accidental BIC in a two-coupled-oscillator system consisting of bilayer gratings,where the optical response of each grating can be described by a single resonator model.By changing the interlayer distance between the gratings to tune the propagation phase shift related to wave vectors,the position of the accidental BIC can be arbitrarily controlled in momentum space.Moreover,we present a general method and rigorous numerical analyses for extracting the polarization vector fields to observe the topological properties of BICs from the polarization-resolved transmission spectra.Finally,an application of the highly efficient second harmonic generation assisted by quasi-BIC is demonstrated.Our work provides a straightforward strategy for manipulating BICs and studying their topological properties in momentum space.
基金National Key Research and Development Program of China(2021YFA1400602)National Natural Science Foundation of China(11974261,62075213,12104105,12274325,11874286,61621001,91850206)。
文摘Metasurfaces with spin-selective transmission play an increasingly critical role in realizing optical chiral responses,especially for strong intrinsic chirality,which is limited to complex three-dimensional geometry.In this paper,we propose a planar metasurface capable of generating maximal intrinsic chirality and achieving dual-band spinselective transmission utilizing dual quasi-bound states in the continuum(quasi-BICs)caused by the structural symmetry breaking.Interestingly,the value of circular dichroism(CD)and the transmittance of two kinds of circular polarization states can be arbitrarily controlled by tuning the asymmetry parameter.Remarkable CD approaching unity with the maximum transmittance up to 0.95 is experimentally achieved in the dual band.Furthermore,assisted by chiral BICs,the application in polarization multiplexed near-field image display is also exhibited.Our work provides a new avenue to flexibly control intrinsic chirality in planar structure and offers an alternative strategy to develop chiral sensing,multiband spin-selective transmission,and high-performance circularly polarized wave detection.The basic principle and design method of our experiments in the microwave regime can be extended to other bands,such as the terahertz and infrared wavelengths.
