The microstructure and mechanical properties of a traditional Ti-microalloyed weathering steel were analyzed,and the strength was improved by proposing an optimized Ti content.The yield strength and elongation of the ...The microstructure and mechanical properties of a traditional Ti-microalloyed weathering steel were analyzed,and the strength was improved by proposing an optimized Ti content.The yield strength and elongation of the steel were 640 MPa and 25.5%,respectively.The microstructure was ferrite and pearlite,and the average grain size was 5.4μm.The precipitates were mainly TiC with the size below 20 nm,and the average diameter was 18.2 nm.The yield strength of the newly proposed weathering steel with Ti content of 0.018%higher than that of the traditional steel reached up to 709 MPa,and the elongation was 23.5%.The ferrite grain was refined to 3.8μm,the fraction of TiC under 10 nm was obviously increased,and the average diameter of particles was 9.8 nm.The increase in Ti also promoted the recrystallization process,thus leading to the reduction in dislocation density.The yield strength of the newly proposed weathering steel was increased to higher than 700 MPa by adjusting the Ti content mainly resulting from three aspects:grain refinement,precipitation and dislocation strengthening.The contributed values were 45,64 and–40 MPa,respectively.展开更多
The effect of intermetallic particles on the corrosion of 6061 aluminum alloy and its coating used in semiconductor processing systems was systematically studied via liquid and gas experiments and micromorphology char...The effect of intermetallic particles on the corrosion of 6061 aluminum alloy and its coating used in semiconductor processing systems was systematically studied via liquid and gas experiments and micromorphology characterization.The results revealed that a huge difference of corrosion resistance between imported and domestic 6061 aluminum alloys in HCl solution and gas acid mist experiments mainly was attributed to the different size and amount of Al_(15)(Fe,Mn)_(3)Si_(2).The corrosion resistance of domestic 6061 alloy in dry/wet semiconductor electronic special gas environments was worse than that of imported aluminum alloy,and there are great differences in the corrosion mechanism of 6061 alloy caused by the second phase in the two dry/wet environments.And the corrosion resistance of the hard anodized alumina film was closely related to the microscopic morphology of holes.The vertical and elongatedα-Al_(15)(Mn,Fe)_(3)Si_(2) phase was formed in the rolled aluminum alloy that has been rolled perpendicular to the surface of the substrate.Compared to the horizontal long hole,the longitudinal long holes generated by the verticalα-Al_(15)(Mn,Fe)_(3)Si_(2) phase will enable the corrosive medium to reach the substrate rapidly,which significantly weakens the corrosion resistance of the hard anodized film.展开更多
OBJECTIVE： To investigate the factors associated with sensory and motor recovery after the repair of upper limb peripheral nerve injuries. DATA SOURCES： The online PubMed database was searched for English articles d...OBJECTIVE： To investigate the factors associated with sensory and motor recovery after the repair of upper limb peripheral nerve injuries. DATA SOURCES： The online PubMed database was searched for English articles describing outcomes after the repair of median, ulnar, radial, and digital nerve injuries in humans with a publication date between 1 January 1990 and 16 February 2011. STUDY SELECTION： The following types of article were selected： （1） clinical trials describ- ing the repair of median, ulnar, radial, and digital nerve injuries published in English; and （2） studies that reported sufficient patient information, including age, mechanism of injury, nerve injured, injury location, defect length, repair time, repair method, and repair materials. SPSS 13.0 software was used to perform univariate and multivariate logistic regression analyses and to in- vestigate the patient and intervention factors associated with outcomes. MAIN OUTCOME MEASURES： Sensory function was assessed using the Mackinnon-Dellon scale and motor function was assessed using the manual muscle test. Satisfactory motor recovery was defined as grade M4 or M5, and satisfactory sensory recovery was defined as grade S3＋ or S4. RESULTS： Seventy-one articles were included in this study. Univariate and multivariate logistic regression analyses showed that repair time, repair materials, and nerve injured were inde- pendent predictors of outcome after the repair of nerve injuries （P 〈 0.05）, and that the nerve injured was the main factor affecting the rate of good to excellent recovery. CONCLUSION： Predictors of outcome after the repair of peripheral nerve injuries include age, gender, repair time, repair materials, nerve injured, defect length, and duration of follow-up.展开更多
Aiming at obtaining an accurate porosity of gas shale,various approaches are attempted.Therein,nuclear magnetic resonance(NMR),being treated as a kind of new-developed technique,possesses the representative significan...Aiming at obtaining an accurate porosity of gas shale,various approaches are attempted.Therein,nuclear magnetic resonance(NMR),being treated as a kind of new-developed technique,possesses the representative significance.However,as a booming technique,the reliability of NMR-based porosity of shale is not exactly defined.Depending on NMR device,this work measured the porosity of shale experiencing different water soaking time,accordingly,judging the reliability of NMR-based porosity.Results indicate the NMR outcomes vary with the water soaking time,making a doubt about the objectivity of NMRbased porosity in reflecting the real shale porosity.Furthermore,some supplementary means were adopted to verify the water soaking-induced variation in the pore system of shale sample,which intensities the suspicion if the NMR-based porosity is reliable or not.To sum up,this work considers that the NMR-based porosity of shale is not reliable enough when water is used as the probe.Besides,this work also offers some suggestions on how to enhance the reliability of NMR-based porosity of shale sample.Basically,this work selects a fresh perspective to analyze the NMR approach in determining shale porosity,which is hopefully helpful in promoting the development of NMR technique in the shale-related field.展开更多
To improve the inconsistency in the analytic hierarchy process(AHP), a new method based on marginal optimization theory is proposed. During the improving process, this paper regards the reduction of consistency ratio(...To improve the inconsistency in the analytic hierarchy process(AHP), a new method based on marginal optimization theory is proposed. During the improving process, this paper regards the reduction of consistency ratio(CR) as benefit, and the maximum modification compared to the original pairwise comparison matrix(PCM) as cost, then the improvement of consistency is transformed to a benefit/cost analysis problem. According to the maximal marginal effect principle, the elements of PCM are modified by a fixed increment(or decrement) step by step till the consistency ratio becomes acceptable, which can ensure minimum adjustment to the original PCM so that the decision makers’ judgment is preserved as much as possible. The correctness of the proposed method is proved mathematically by theorem. Firstly, the marginal benefit/cost ratio is calculated for each single element of the PCM when it has been modified by a fixed increment(or decrement).Then, modification to the element with the maximum marginal benefit/cost ratio is accepted. Next, the marginal benefit/cost ratio is calculated again upon the revised matrix, and followed by choosing the modification to the element with the maximum marginal benefit/cost ratio. The process of calculating marginal effect and choosing the best modified element is repeated for each revised matrix till acceptable consistency is reached, i.e., CR<0.1. Finally,illustrative examples show the proposed method is more effective and better in preserving the original comparison information than existing methods.展开更多
Laser shock peening(LSP)is an attractive post-processing method to tailor surface microstructure and enhance mechanical performances of additive manufactured(AM)components.The effects of multiple LSP treatments on the...Laser shock peening(LSP)is an attractive post-processing method to tailor surface microstructure and enhance mechanical performances of additive manufactured(AM)components.The effects of multiple LSP treatments on the microstructure and mechanical properties of Ti-6Al-4V part produced by electron beam melting(EBM),as a mature AM process,were studied in this work.Microstructure,surface topography,residual stress,and tensile performance of EBM-manufactured Ti-6Al-4V specimens were systematically analyzed subjected to different LSP treatments.The distribution of porosities in EBM sample was assessed via X-ray computed tomography.The results showed that EBM samples with two LSP treatments possessed a lower porosity value of 0.05%compared to the value of 0.08%for the untreated samples.The strength of EBM samples with two LSP treatments was remarkably raised by 12%as compared with the as-built samples.The grains ofαphase were refined in near-surface layer,and a dramatic increase in the depth and magnitude of compressive residual stress(CRS)was achieved in EBM sample with multiple LSP treatments.The grain refinement ofαphase and CRS with larger depth were responsible for the strength enhancement of EBM samples with two LSP treatments.展开更多
In this work, a novel thermal–hydraulic–mechanical (THM) coupling model is developed, where the real geological parameters of the reservoir properties are embedded. Accordingly, nine schemes of CO_(2) injection well...In this work, a novel thermal–hydraulic–mechanical (THM) coupling model is developed, where the real geological parameters of the reservoir properties are embedded. Accordingly, nine schemes of CO_(2) injection well (IW) and CH_(4) production well (PW) are established, aiming to explore the behavior of free gases after CO_(2) is injected into the depleted Wufeng–Longmaxi shale. The results indicate the free CH4 or CO2 content in the shale fractures/matrix is invariably heterogeneous. The CO_(2) involvement facilitates the ratio of free CH_(4)/CO_(2) in the matrix to that in the fractures declines and tends to be stable with time. Different combinations of IW–PWs induce a difference in the ratio of the free CH4 to the free CO_(2), in the ratio of the free CH_(4)/CO_(2) in the matrix to that in the fractures, in the content of the recovered free CH_(4), and in the content of the trapped free CO_(2). Basically, when the IW locates at the bottom Wufeng–Longmaxi shale, a farther IW–PWs distance allows more CO2 in the free phase to be trapped;furthermore, no matter where the IW is, a shorter IW–PWs distance benefits by getting more CH_(4) in the free phase recovered from the depleted Wufeng–Longmaxi shale. Hopefully, this work is helpful in gaining knowledge about the shale-based CO_(2) injection technique.展开更多
The Shanghai soft X-ray free-electron laser(SXFEL)user facility project started in 2016 and is expected to be open to users by 2022.It aims to deliver ultra-intense coherent femtosecond X-ray pulses to five endstation...The Shanghai soft X-ray free-electron laser(SXFEL)user facility project started in 2016 and is expected to be open to users by 2022.It aims to deliver ultra-intense coherent femtosecond X-ray pulses to five endstations covering a range of 100–620 eV for ultrafast X-ray science.Two undulator lines are designed and constructed,based on different lasing modes:self-amplified spontaneous emission and echo-enabled harmonic generation.The coherent scattering and imaging(CSI)endstation is the first of five endstations to be commissioned online.It focuses on high-resolution single-shot imaging and the study of ultrafast dynamic processes using coherent forward scattering techniques.Both the single-shot holograms and coherent diffraction patterns were recorded and reconstructed for nanoscale imaging,indicating the excellent coherence and high peak power of the SXFEL and the possibility of‘‘diffraction before destruction’’experiments at the CSI endstation.In this study,we report the first commissioning results of the CSI endstation.展开更多
An infrared detector with high responsivity based on graphene-PbSe thin film heterojunction was reported.High-quality PbSe thin film and graphene were prepared by molecular beam epitaxy and chemical vapor deposition,r...An infrared detector with high responsivity based on graphene-PbSe thin film heterojunction was reported.High-quality PbSe thin film and graphene were prepared by molecular beam epitaxy and chemical vapor deposition,respectively.The physical characteristics of PbSe thin film and graphene were performed using X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS)and Raman measurement.The photo transistor using PbSe thin film as a sensitizer and graphene as a channel to transport excitons exhibits peak responsivity and detectivity up to~420 A·W^(-1) and 5.9×10^(11) Jones(radiation intensity:0.75 mW·cm^(-2))at room temperature in the near-infrared(NIR)region,respectively.The high optical response is attributed to the photo-excited holes transferring from PbSe film to graphene under irradiation.Moreover,it is revealed that the responsivity of graphene-PbSe photo transistor is gate-tunable which is important in photodetectors.展开更多
Aurum nanomaterials(ANM), combining the features of nanotechnology and metal elements, have demonstrated enormous potential and aroused great attention on biomedical applications over the past few decades. Particularl...Aurum nanomaterials(ANM), combining the features of nanotechnology and metal elements, have demonstrated enormous potential and aroused great attention on biomedical applications over the past few decades. Particularly, their advantages, such as controllable particle size, flexible surface modification, higher drug loading, good stability and biocompatibility, especially unique optical properties, promote the development of ANM in biomedical field. In this review, we will discuss the advanced preparation process of ANM and summarize their recent applications as well as their prospects in diagnosis and therapy. Besides, multi-functional ANM-based theranostic nanosystems will be introduced in details, including radiotherapy(RT), photothermal therapy(PTT), photodynamic therapy(PDT), immunotherapy(IT), and so on.展开更多
Corrosion behavior of Cu-P-Cr-Ni weathering steels with different nickel contents was studied by periodic immersion corrosion test for 72 h.The mass loss method was used to evaluate the weatherability of weathering st...Corrosion behavior of Cu-P-Cr-Ni weathering steels with different nickel contents was studied by periodic immersion corrosion test for 72 h.The mass loss method was used to evaluate the weatherability of weathering steel.The rust layers formed on weathering steel were characterized by scanning electron microscopy,X-ray diffraction,electron probe microanalysis,X-ray photoelectron spectroscopy,and electrochemical measurements.The results of periodic immersion corrosion test for 72 h showed that the mass loss rates of Cu-P-Cr-0.14Ni steel and Cu-P-Cr-0.04Ni steel were 1.57 and 1.61 g/(m^(2)h),respectively.According to the electrochemical experiment,the corrosion potentials of the two tested steels at the initial stage of corrosion were-0.6852 and-0.7037 V,respectively.With the corrosion time reaching 72 h,the corrosion potential difference between the two tested steels was gradually reduced.In the initial stage,NiO was formed in the rust layer and can dramatically promote the crystallization of corrosion products to improve the stability of the rust layer.After periodic immersion corrosion test for 72 h,Ni element had no obvious effect.At this time,it was mainly the enrichment of Cu and Cr elements in the form of CuO and Cr_(2)O_(3)in the rust layer that could further protect the matrix.展开更多
The proper development of uterus to a state of receptivity and the attainment of implantation competency for blastocyst are 2 indispensable aspects for implantation,which is considered to be a critical event for succe...The proper development of uterus to a state of receptivity and the attainment of implantation competency for blastocyst are 2 indispensable aspects for implantation,which is considered to be a critical event for successful pregnancy. Like many developmental processes, a large number of transcription factors, such as homeobox genes, have been shown to orchestrate this complicated but highly organized physiological process during implantation. In this review, we focus on progress in studies of the role of homeobox genes, especially the Hox and Msx gene families, during implantation, together with subsequent development of post-implantation uterus and related reproductive defects in both mouse models and humans, that have led to better understanding of how implantation is precisely regulated and provide new insights into infertility.展开更多
4-Hydrophenylpyruvate dioxygenase(HPPD),a key enzyme involved in tyrosine catabolism,has long been considered a promising target for herbicides and drugs.Several types of HPPD inhibitors have been developed as high-po...4-Hydrophenylpyruvate dioxygenase(HPPD),a key enzyme involved in tyrosine catabolism,has long been considered a promising target for herbicides and drugs.Several types of HPPD inhibitors have been developed as high-potency drugs or herbicides.Understanding the structural basis of the binding of these inhibitors with HPPD will be beneficial for the development of inhibitors containing novel scaffolds.However,only limited structural information regarding the binding of triketone and pyrazole derivatives with HPPD has been reported.Here,the crystal structures of HPPD complexed with inhibitors containing different scaffolds,including triketone,pyrazole,isoxazole,heterocyclic amide,and quinazolindione derivatives,were comprehensively analyzed.Detailed binding modes of isoxazole and heterocyclic amide derivatives with HPPD were first revealed,facilitating further structural optimization.The binding mode of compound 2 with HPPD suggests that both oxygen and nitrogen atoms can mediate coordination with the metal ion.These results will provide the structure-based rational design of novel HPPD inhibitors.展开更多
Exploring plant behavior at the cellular scale in a minimally invasive manner is critical to understanding plant adaptation to the environment.Phytohormones play vital regulatory roles in multiple aspects of plant gro...Exploring plant behavior at the cellular scale in a minimally invasive manner is critical to understanding plant adaptation to the environment.Phytohormones play vital regulatory roles in multiple aspects of plant growth and development and acclimation to environmental changes.Since the biosynthesis,modification,transportation,and degradation of plant hormones in plants change with time and space,their content level and distribution are highly dynamic.To monitor the production,transport,perception,and distribution of phytohormones within undamaged tissues,we require qualitative and quantitative tools endowed with remarkably high temporal and spatial resolution.Fluorescent probes are regarded as excellent tools for widespread plant imaging because of their high sensitivity and selectivity,reproducibility,real-time in situ detection,and uncomplicated mechanism elucidation.In this review,we provide a systematical overview of the progress in the sensing and imaging of phytohormone fluorescent probes and fluorescently labeled phytohormones to their receptors in plants.Moreover,forthcoming viewpoints and possible applications of these fluorescent probes within the realm of plants are also presented.We hold the conviction that the new perspective brought by this paper can promote the development of fluorescent probes,enabling them to have better detection performance in plant hormone imaging.展开更多
Objective:To evaluate the changes in serum index levels after monosialoganglioside injection combined with conventional treatment of neonatal hypoxic ischemic encephalopathy. Methods:A total of 70 children with neonat...Objective:To evaluate the changes in serum index levels after monosialoganglioside injection combined with conventional treatment of neonatal hypoxic ischemic encephalopathy. Methods:A total of 70 children with neonatal hypoxic ischemic encephalopathy treated in our hospital between February 2013 and February 2016 were selected and randomly divided into observation group and control group, control group received clinical routine treatment and observation group accepted monosialoganglioside injection combined with conventional treatment. After 1 week of treatment, serum levels of apoptosis factors, nerve function indexes, oxidation/anti-oxidation indexes and disease severity indexes of two groups of patients were detected.Results:Serum PDCD5, sFas, sFasL, NSE, S100-β, MDA, NO, NOS, H-FABP, NPY, caspase-1 and ET-1 levels of observation group were lower than those of control group while BDNF, NGF, SOD, GSH-PX, IGF-1 and GH levels were higher than those of control group.Conclusion: Monosialoganglioside injection can enhance the overall treatment effect and promote the realization of homeostasis in children with HIE.展开更多
Objective:Investigation of the regulatory mechanisms of cell stemness in cholangiocarcinoma(CCA)is essential for developing effective therapies to improve patient outcomes.The purpose of this study was to investigate ...Objective:Investigation of the regulatory mechanisms of cell stemness in cholangiocarcinoma(CCA)is essential for developing effective therapies to improve patient outcomes.The purpose of this study was to investigate the function and regulatory mechanism of m6A modifications in CCA cell stemness.Methods:Interleukin 6(IL-6)treatment was used to induce an inflammatory response,and loss-of-function studies were conducted using mammosphere culture assays.Chromatin immunoprecipitation,polysome profiling,and methylated RNA immunoprecipitation analyses were used to identify signaling pathways.The in vitro findings were verified in a mice model.Results:We first identified that m6A writers were highly expressed in CCAs and further showed that STAT3 directly bound to the gene loci of m6A writers,showing that IL-6/STAT3 signaling regulated expressions of m6A writers.Downregulating m6A writers prevented cell proliferation and migration in vitro and suppressed CCA tumorigenesis in vivo.Notably,the knockdown of m6A writers inhibited CCA cell stemness that was triggered by IL-6 treatment.Mechanistically,IGF2BP2 was bound to CTNNB1 transcripts,significantly enhancing their stability and translation,and conferring stem-like properties.Finally,we confirmed that the combination of m6A writers,IGF2BP2,and CTNNB1 distinguished CCA tissues from normal tissues.Conclusions:Overall,this study showed that the IL-6-triggered inflammatory response facilitated the expressions of m6A writers and cell stemness in an m6A-IGF2BP2-dependent manner.Furthermore,the study showed that m6A modification was a targetable mediator of the response to inflammation factor exposure,was a potential diagnostic biomarker for CCA,and was critical to the progression of CCA.展开更多
As an important lightning protection device in substations,lightning rods are susceptible to vibration and potential structural damage under wind loads.In order to understand their vibration mechanism,it is necessary ...As an important lightning protection device in substations,lightning rods are susceptible to vibration and potential structural damage under wind loads.In order to understand their vibration mechanism,it is necessary to conduct flow analysis.In this study,numerical simulations of the flow field around a 330 kV cylindrical lightning rod with different diameters were performed using the SST k-ωmodel.The flow patterns in different segments of the lightning rod at the same reference wind speed(wind speed at a height of 10 m)and the flow patterns in the same segment at different reference wind speeds were investigated.The variations of lift coefficient,drag coefficient,and vorticity distribution were obtained.The results showed that vortex shedding phenomena occurred in all segments of the lightning rod,and the strength of vortex shedding increased with decreasing diameter.The vorticity magnitude and the root mean square magnitudes of the lift coefficient and drag coefficient also increased accordingly.The time history curves of the lift coefficient and drag coefficient on the surface of the lightning rod exhibited sinusoidal patterns with a single dominant frequency.For the same segment,as the wind speed increased in a certain range,the root mean square values of the lift coefficient and drag coefficient decreased,while their dominant frequencies increased.Moreover,there was a proportional relationship between the dominant frequencies of the lift coefficient and drag coefficient.The findings of this study can provide valuable insights for the refined design of lightning rods with similar structures.展开更多
When using high-voltage transmission lines for energy transmission in loess hilly regions,local extreme wind fields such as turbulence and high-speed cyclones occur from time to time,which can cause many kinds of mech...When using high-voltage transmission lines for energy transmission in loess hilly regions,local extreme wind fields such as turbulence and high-speed cyclones occur from time to time,which can cause many kinds of mechanical and electrical failures,seriously affecting the reliable and stable energy transmission of the power grid.The existing research focuses on the wind field simulation of ideal micro-terrain and actual terrain with mostly single microterrain characteristics.Model boundary constraints and the influence of constrained boundaries are the main problems that need to be solved to accurately model and simulate complex flow fields.In this paper,a flow field simulation method based on circular boundary constraints is carried out.During the study,the influence of the model boundary and the selection conditions of themodeling range are systematically analyzed.It is more suitable to make sure that the air domain is 4 times higher than the height of the hill undulations,in addition to ensuring that there should be a minimum of 400 m between the study region and the boundary.Then,an actual terrain model of a power grid line in Shanxi is established,through the method proposed in this paper,the wind speed at the location of the transmission tower line under different wind directions is analyzed,and it is found that when the incidence direction is 45 degrees north by east the wind speed is the highest.The findings demonstrate that the circular boundary model has the advantage of more easily adjusting the wind incidence direction,in addition to theoretically reducing the errors caused by traditional models in boundary processing.It can accurately obtain the distribution characteristics of the flow field affected by the terrain,and quickly screen out the extreme working conditions that are most harmful to the transmission lines in the actual transmission line for energy transmission in complex loess hilly regions.展开更多
[4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid(Me-4PACz)self-assembled monolayer(SAM)as the hole transport materials have been demonstrated remarkable potential in perovskite solar cells(PSCs).However,the hyd...[4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid(Me-4PACz)self-assembled monolayer(SAM)as the hole transport materials have been demonstrated remarkable potential in perovskite solar cells(PSCs).However,the hydrophobicity of Me-4PACz presents a critical challenge for the fabrication of high-quality perovskite films due to its poor wettability.Here,a doped Al_(2)O_(3)with Me-4PACz to modify the Me-4PACz surface was proposed.On one hand,this approach improved the wettability of the Me-4PACz film,enhancing the coverage,uniformity,and buried interface properties of the perovskite film.On the other hand,compared to Al_(2)O_(3)modification alone,doping Al_(2)O_(3)with Me-4PACz allowed direct contact between the perovskite and Me-4PACz,resulting in better buried interface passivation.As a result,we achieved an efficiency of 22.71%for single-junction wide-bandgap perovskite solar cells(1.68 eV).Additionally,the efficiency of perovskite/silicon tandem solar cells was improved from 28.68%to 30.92%,with a significant reduction in hysteresis.Furthermore,the tandem cells demonstrated no degradation after 4200 s of operation at the maximum power point.展开更多
基金support from Maanshan Iron&Steel Co.,Ltd.and student research training project of University of Science and Technology Beijing.
文摘The microstructure and mechanical properties of a traditional Ti-microalloyed weathering steel were analyzed,and the strength was improved by proposing an optimized Ti content.The yield strength and elongation of the steel were 640 MPa and 25.5%,respectively.The microstructure was ferrite and pearlite,and the average grain size was 5.4μm.The precipitates were mainly TiC with the size below 20 nm,and the average diameter was 18.2 nm.The yield strength of the newly proposed weathering steel with Ti content of 0.018%higher than that of the traditional steel reached up to 709 MPa,and the elongation was 23.5%.The ferrite grain was refined to 3.8μm,the fraction of TiC under 10 nm was obviously increased,and the average diameter of particles was 9.8 nm.The increase in Ti also promoted the recrystallization process,thus leading to the reduction in dislocation density.The yield strength of the newly proposed weathering steel was increased to higher than 700 MPa by adjusting the Ti content mainly resulting from three aspects:grain refinement,precipitation and dislocation strengthening.The contributed values were 45,64 and–40 MPa,respectively.
基金financially supported by the Program of the National Natural Science Foundation of China(Grant No.52371055)the Young Elite Scientist Sponsorship Program Cast(Grant No.YESS20200139)the Basic Scientific Research Project of Liaoning Provincial Department of Education(Grant No.JYTMS20230618)。
文摘The effect of intermetallic particles on the corrosion of 6061 aluminum alloy and its coating used in semiconductor processing systems was systematically studied via liquid and gas experiments and micromorphology characterization.The results revealed that a huge difference of corrosion resistance between imported and domestic 6061 aluminum alloys in HCl solution and gas acid mist experiments mainly was attributed to the different size and amount of Al_(15)(Fe,Mn)_(3)Si_(2).The corrosion resistance of domestic 6061 alloy in dry/wet semiconductor electronic special gas environments was worse than that of imported aluminum alloy,and there are great differences in the corrosion mechanism of 6061 alloy caused by the second phase in the two dry/wet environments.And the corrosion resistance of the hard anodized alumina film was closely related to the microscopic morphology of holes.The vertical and elongatedα-Al_(15)(Mn,Fe)_(3)Si_(2) phase was formed in the rolled aluminum alloy that has been rolled perpendicular to the surface of the substrate.Compared to the horizontal long hole,the longitudinal long holes generated by the verticalα-Al_(15)(Mn,Fe)_(3)Si_(2) phase will enable the corrosive medium to reach the substrate rapidly,which significantly weakens the corrosion resistance of the hard anodized film.
基金supported by the National High-Technology Research and Development Program of China(863 Program),No.2012A A020507985 Program of Sun Yat-sen University,No.90035-3283312+1 种基金Specialized Research Fund for the Doctoral Program of Higher Education,No.20120171120075Doctoral Start-up Project of the Natural Science Foundation of Guangdong Province,No.S201204006336
文摘OBJECTIVE： To investigate the factors associated with sensory and motor recovery after the repair of upper limb peripheral nerve injuries. DATA SOURCES： The online PubMed database was searched for English articles describing outcomes after the repair of median, ulnar, radial, and digital nerve injuries in humans with a publication date between 1 January 1990 and 16 February 2011. STUDY SELECTION： The following types of article were selected： （1） clinical trials describ- ing the repair of median, ulnar, radial, and digital nerve injuries published in English; and （2） studies that reported sufficient patient information, including age, mechanism of injury, nerve injured, injury location, defect length, repair time, repair method, and repair materials. SPSS 13.0 software was used to perform univariate and multivariate logistic regression analyses and to in- vestigate the patient and intervention factors associated with outcomes. MAIN OUTCOME MEASURES： Sensory function was assessed using the Mackinnon-Dellon scale and motor function was assessed using the manual muscle test. Satisfactory motor recovery was defined as grade M4 or M5, and satisfactory sensory recovery was defined as grade S3＋ or S4. RESULTS： Seventy-one articles were included in this study. Univariate and multivariate logistic regression analyses showed that repair time, repair materials, and nerve injured were inde- pendent predictors of outcome after the repair of nerve injuries （P 〈 0.05）, and that the nerve injured was the main factor affecting the rate of good to excellent recovery. CONCLUSION： Predictors of outcome after the repair of peripheral nerve injuries include age, gender, repair time, repair materials, nerve injured, defect length, and duration of follow-up.
基金financially supported by the Science and Technology Department of Sichuan Province(Grant Nos.2021YFH0048 and 2021YFH0118)the Project funded by China Postdoctoral Science Foundation(Grant No.2020M683253)
文摘Aiming at obtaining an accurate porosity of gas shale,various approaches are attempted.Therein,nuclear magnetic resonance(NMR),being treated as a kind of new-developed technique,possesses the representative significance.However,as a booming technique,the reliability of NMR-based porosity of shale is not exactly defined.Depending on NMR device,this work measured the porosity of shale experiencing different water soaking time,accordingly,judging the reliability of NMR-based porosity.Results indicate the NMR outcomes vary with the water soaking time,making a doubt about the objectivity of NMRbased porosity in reflecting the real shale porosity.Furthermore,some supplementary means were adopted to verify the water soaking-induced variation in the pore system of shale sample,which intensities the suspicion if the NMR-based porosity is reliable or not.To sum up,this work considers that the NMR-based porosity of shale is not reliable enough when water is used as the probe.Besides,this work also offers some suggestions on how to enhance the reliability of NMR-based porosity of shale sample.Basically,this work selects a fresh perspective to analyze the NMR approach in determining shale porosity,which is hopefully helpful in promoting the development of NMR technique in the shale-related field.
基金supported by the National Natural Science Foundation of China(6160150161502521)
文摘To improve the inconsistency in the analytic hierarchy process(AHP), a new method based on marginal optimization theory is proposed. During the improving process, this paper regards the reduction of consistency ratio(CR) as benefit, and the maximum modification compared to the original pairwise comparison matrix(PCM) as cost, then the improvement of consistency is transformed to a benefit/cost analysis problem. According to the maximal marginal effect principle, the elements of PCM are modified by a fixed increment(or decrement) step by step till the consistency ratio becomes acceptable, which can ensure minimum adjustment to the original PCM so that the decision makers’ judgment is preserved as much as possible. The correctness of the proposed method is proved mathematically by theorem. Firstly, the marginal benefit/cost ratio is calculated for each single element of the PCM when it has been modified by a fixed increment(or decrement).Then, modification to the element with the maximum marginal benefit/cost ratio is accepted. Next, the marginal benefit/cost ratio is calculated again upon the revised matrix, and followed by choosing the modification to the element with the maximum marginal benefit/cost ratio. The process of calculating marginal effect and choosing the best modified element is repeated for each revised matrix till acceptable consistency is reached, i.e., CR<0.1. Finally,illustrative examples show the proposed method is more effective and better in preserving the original comparison information than existing methods.
基金financially supported by the Shanghai Science and Technology Committee Innovation Grant(Nos.17JC1400600 and 17JC1400603)the Distinguished Professor Program of Shanghai University of Engineering Science。
文摘Laser shock peening(LSP)is an attractive post-processing method to tailor surface microstructure and enhance mechanical performances of additive manufactured(AM)components.The effects of multiple LSP treatments on the microstructure and mechanical properties of Ti-6Al-4V part produced by electron beam melting(EBM),as a mature AM process,were studied in this work.Microstructure,surface topography,residual stress,and tensile performance of EBM-manufactured Ti-6Al-4V specimens were systematically analyzed subjected to different LSP treatments.The distribution of porosities in EBM sample was assessed via X-ray computed tomography.The results showed that EBM samples with two LSP treatments possessed a lower porosity value of 0.05%compared to the value of 0.08%for the untreated samples.The strength of EBM samples with two LSP treatments was remarkably raised by 12%as compared with the as-built samples.The grains ofαphase were refined in near-surface layer,and a dramatic increase in the depth and magnitude of compressive residual stress(CRS)was achieved in EBM sample with multiple LSP treatments.The grain refinement ofαphase and CRS with larger depth were responsible for the strength enhancement of EBM samples with two LSP treatments.
基金This study was financially supported by the National Natural Science Foundation of China(Grant Nos.51704197 and 11872258)。
文摘In this work, a novel thermal–hydraulic–mechanical (THM) coupling model is developed, where the real geological parameters of the reservoir properties are embedded. Accordingly, nine schemes of CO_(2) injection well (IW) and CH_(4) production well (PW) are established, aiming to explore the behavior of free gases after CO_(2) is injected into the depleted Wufeng–Longmaxi shale. The results indicate the free CH4 or CO2 content in the shale fractures/matrix is invariably heterogeneous. The CO_(2) involvement facilitates the ratio of free CH_(4)/CO_(2) in the matrix to that in the fractures declines and tends to be stable with time. Different combinations of IW–PWs induce a difference in the ratio of the free CH4 to the free CO_(2), in the ratio of the free CH_(4)/CO_(2) in the matrix to that in the fractures, in the content of the recovered free CH_(4), and in the content of the trapped free CO_(2). Basically, when the IW locates at the bottom Wufeng–Longmaxi shale, a farther IW–PWs distance allows more CO2 in the free phase to be trapped;furthermore, no matter where the IW is, a shorter IW–PWs distance benefits by getting more CH_(4) in the free phase recovered from the depleted Wufeng–Longmaxi shale. Hopefully, this work is helpful in gaining knowledge about the shale-based CO_(2) injection technique.
基金the Shanghai Soft X-ray Free-Electron Laser Facility beamline projectionfunded by the Major State Basic Research Development Program of China(No.2017YFA0504802)+1 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB 37040303)National Natural Science Foundation of China(No.21727817).
文摘The Shanghai soft X-ray free-electron laser(SXFEL)user facility project started in 2016 and is expected to be open to users by 2022.It aims to deliver ultra-intense coherent femtosecond X-ray pulses to five endstations covering a range of 100–620 eV for ultrafast X-ray science.Two undulator lines are designed and constructed,based on different lasing modes:self-amplified spontaneous emission and echo-enabled harmonic generation.The coherent scattering and imaging(CSI)endstation is the first of five endstations to be commissioned online.It focuses on high-resolution single-shot imaging and the study of ultrafast dynamic processes using coherent forward scattering techniques.Both the single-shot holograms and coherent diffraction patterns were recorded and reconstructed for nanoscale imaging,indicating the excellent coherence and high peak power of the SXFEL and the possibility of‘‘diffraction before destruction’’experiments at the CSI endstation.In this study,we report the first commissioning results of the CSI endstation.
基金financially supported by the National Natural Science Foundation of China(No.51572043)。
文摘An infrared detector with high responsivity based on graphene-PbSe thin film heterojunction was reported.High-quality PbSe thin film and graphene were prepared by molecular beam epitaxy and chemical vapor deposition,respectively.The physical characteristics of PbSe thin film and graphene were performed using X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS)and Raman measurement.The photo transistor using PbSe thin film as a sensitizer and graphene as a channel to transport excitons exhibits peak responsivity and detectivity up to~420 A·W^(-1) and 5.9×10^(11) Jones(radiation intensity:0.75 mW·cm^(-2))at room temperature in the near-infrared(NIR)region,respectively.The high optical response is attributed to the photo-excited holes transferring from PbSe film to graphene under irradiation.Moreover,it is revealed that the responsivity of graphene-PbSe photo transistor is gate-tunable which is important in photodetectors.
基金Supported by the National Basic Research Program of China(2015CB932100)
文摘Aurum nanomaterials(ANM), combining the features of nanotechnology and metal elements, have demonstrated enormous potential and aroused great attention on biomedical applications over the past few decades. Particularly, their advantages, such as controllable particle size, flexible surface modification, higher drug loading, good stability and biocompatibility, especially unique optical properties, promote the development of ANM in biomedical field. In this review, we will discuss the advanced preparation process of ANM and summarize their recent applications as well as their prospects in diagnosis and therapy. Besides, multi-functional ANM-based theranostic nanosystems will be introduced in details, including radiotherapy(RT), photothermal therapy(PTT), photodynamic therapy(PDT), immunotherapy(IT), and so on.
基金The authors appreciate the financial support from Maanshan Iron&Steel Co,Ltd.and Student Research Training Program of University of Science and Technology Beijing.
文摘Corrosion behavior of Cu-P-Cr-Ni weathering steels with different nickel contents was studied by periodic immersion corrosion test for 72 h.The mass loss method was used to evaluate the weatherability of weathering steel.The rust layers formed on weathering steel were characterized by scanning electron microscopy,X-ray diffraction,electron probe microanalysis,X-ray photoelectron spectroscopy,and electrochemical measurements.The results of periodic immersion corrosion test for 72 h showed that the mass loss rates of Cu-P-Cr-0.14Ni steel and Cu-P-Cr-0.04Ni steel were 1.57 and 1.61 g/(m^(2)h),respectively.According to the electrochemical experiment,the corrosion potentials of the two tested steels at the initial stage of corrosion were-0.6852 and-0.7037 V,respectively.With the corrosion time reaching 72 h,the corrosion potential difference between the two tested steels was gradually reduced.In the initial stage,NiO was formed in the rust layer and can dramatically promote the crystallization of corrosion products to improve the stability of the rust layer.After periodic immersion corrosion test for 72 h,Ni element had no obvious effect.At this time,it was mainly the enrichment of Cu and Cr elements in the form of CuO and Cr_(2)O_(3)in the rust layer that could further protect the matrix.
基金National Natural Science Foundation of China,Grant/Award Number:81330017,81490744National Key R&D Program of China,Grant/Award Number:2017YFC1001402
文摘The proper development of uterus to a state of receptivity and the attainment of implantation competency for blastocyst are 2 indispensable aspects for implantation,which is considered to be a critical event for successful pregnancy. Like many developmental processes, a large number of transcription factors, such as homeobox genes, have been shown to orchestrate this complicated but highly organized physiological process during implantation. In this review, we focus on progress in studies of the role of homeobox genes, especially the Hox and Msx gene families, during implantation, together with subsequent development of post-implantation uterus and related reproductive defects in both mouse models and humans, that have led to better understanding of how implantation is precisely regulated and provide new insights into infertility.
基金funded in part by the National Key Research and Development Program of China(No.2021YFD1700100)National Natural Science Foundation of China(No.22007035,21837001).
文摘4-Hydrophenylpyruvate dioxygenase(HPPD),a key enzyme involved in tyrosine catabolism,has long been considered a promising target for herbicides and drugs.Several types of HPPD inhibitors have been developed as high-potency drugs or herbicides.Understanding the structural basis of the binding of these inhibitors with HPPD will be beneficial for the development of inhibitors containing novel scaffolds.However,only limited structural information regarding the binding of triketone and pyrazole derivatives with HPPD has been reported.Here,the crystal structures of HPPD complexed with inhibitors containing different scaffolds,including triketone,pyrazole,isoxazole,heterocyclic amide,and quinazolindione derivatives,were comprehensively analyzed.Detailed binding modes of isoxazole and heterocyclic amide derivatives with HPPD were first revealed,facilitating further structural optimization.The binding mode of compound 2 with HPPD suggests that both oxygen and nitrogen atoms can mediate coordination with the metal ion.These results will provide the structure-based rational design of novel HPPD inhibitors.
基金supported by the National Key Research and Development Program of China(2022YFD1700300,2022YFE0199800)the National Natural Science Foundation of China(32072443,82104065,32061143045)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20201323)the Distinguished Young Research Project of Anhui Higher Education Institution(2022AH020035).
文摘Exploring plant behavior at the cellular scale in a minimally invasive manner is critical to understanding plant adaptation to the environment.Phytohormones play vital regulatory roles in multiple aspects of plant growth and development and acclimation to environmental changes.Since the biosynthesis,modification,transportation,and degradation of plant hormones in plants change with time and space,their content level and distribution are highly dynamic.To monitor the production,transport,perception,and distribution of phytohormones within undamaged tissues,we require qualitative and quantitative tools endowed with remarkably high temporal and spatial resolution.Fluorescent probes are regarded as excellent tools for widespread plant imaging because of their high sensitivity and selectivity,reproducibility,real-time in situ detection,and uncomplicated mechanism elucidation.In this review,we provide a systematical overview of the progress in the sensing and imaging of phytohormone fluorescent probes and fluorescently labeled phytohormones to their receptors in plants.Moreover,forthcoming viewpoints and possible applications of these fluorescent probes within the realm of plants are also presented.We hold the conviction that the new perspective brought by this paper can promote the development of fluorescent probes,enabling them to have better detection performance in plant hormone imaging.
文摘Objective:To evaluate the changes in serum index levels after monosialoganglioside injection combined with conventional treatment of neonatal hypoxic ischemic encephalopathy. Methods:A total of 70 children with neonatal hypoxic ischemic encephalopathy treated in our hospital between February 2013 and February 2016 were selected and randomly divided into observation group and control group, control group received clinical routine treatment and observation group accepted monosialoganglioside injection combined with conventional treatment. After 1 week of treatment, serum levels of apoptosis factors, nerve function indexes, oxidation/anti-oxidation indexes and disease severity indexes of two groups of patients were detected.Results:Serum PDCD5, sFas, sFasL, NSE, S100-β, MDA, NO, NOS, H-FABP, NPY, caspase-1 and ET-1 levels of observation group were lower than those of control group while BDNF, NGF, SOD, GSH-PX, IGF-1 and GH levels were higher than those of control group.Conclusion: Monosialoganglioside injection can enhance the overall treatment effect and promote the realization of homeostasis in children with HIE.
基金supported by the National Natural Science Foundation of China(Grant No.81772621)the National Key R&D Program of China(Grant No.2017YFA0504400).
文摘Objective:Investigation of the regulatory mechanisms of cell stemness in cholangiocarcinoma(CCA)is essential for developing effective therapies to improve patient outcomes.The purpose of this study was to investigate the function and regulatory mechanism of m6A modifications in CCA cell stemness.Methods:Interleukin 6(IL-6)treatment was used to induce an inflammatory response,and loss-of-function studies were conducted using mammosphere culture assays.Chromatin immunoprecipitation,polysome profiling,and methylated RNA immunoprecipitation analyses were used to identify signaling pathways.The in vitro findings were verified in a mice model.Results:We first identified that m6A writers were highly expressed in CCAs and further showed that STAT3 directly bound to the gene loci of m6A writers,showing that IL-6/STAT3 signaling regulated expressions of m6A writers.Downregulating m6A writers prevented cell proliferation and migration in vitro and suppressed CCA tumorigenesis in vivo.Notably,the knockdown of m6A writers inhibited CCA cell stemness that was triggered by IL-6 treatment.Mechanistically,IGF2BP2 was bound to CTNNB1 transcripts,significantly enhancing their stability and translation,and conferring stem-like properties.Finally,we confirmed that the combination of m6A writers,IGF2BP2,and CTNNB1 distinguished CCA tissues from normal tissues.Conclusions:Overall,this study showed that the IL-6-triggered inflammatory response facilitated the expressions of m6A writers and cell stemness in an m6A-IGF2BP2-dependent manner.Furthermore,the study showed that m6A modification was a targetable mediator of the response to inflammation factor exposure,was a potential diagnostic biomarker for CCA,and was critical to the progression of CCA.
基金supported by State Grid Ningxia Electric Power Co.,Ltd.under Grant 5229CG220006Natural Science Foundation of Ningxia Province under Grant 2022AAC03629.
文摘As an important lightning protection device in substations,lightning rods are susceptible to vibration and potential structural damage under wind loads.In order to understand their vibration mechanism,it is necessary to conduct flow analysis.In this study,numerical simulations of the flow field around a 330 kV cylindrical lightning rod with different diameters were performed using the SST k-ωmodel.The flow patterns in different segments of the lightning rod at the same reference wind speed(wind speed at a height of 10 m)and the flow patterns in the same segment at different reference wind speeds were investigated.The variations of lift coefficient,drag coefficient,and vorticity distribution were obtained.The results showed that vortex shedding phenomena occurred in all segments of the lightning rod,and the strength of vortex shedding increased with decreasing diameter.The vorticity magnitude and the root mean square magnitudes of the lift coefficient and drag coefficient also increased accordingly.The time history curves of the lift coefficient and drag coefficient on the surface of the lightning rod exhibited sinusoidal patterns with a single dominant frequency.For the same segment,as the wind speed increased in a certain range,the root mean square values of the lift coefficient and drag coefficient decreased,while their dominant frequencies increased.Moreover,there was a proportional relationship between the dominant frequencies of the lift coefficient and drag coefficient.The findings of this study can provide valuable insights for the refined design of lightning rods with similar structures.
基金supported by a State Grid Shanxi Company’s Science and Technology Project—Research on Grid Wind Farm Condition Monitoring of Transmission Lines in Loess Hilly Regions (520530220005).
文摘When using high-voltage transmission lines for energy transmission in loess hilly regions,local extreme wind fields such as turbulence and high-speed cyclones occur from time to time,which can cause many kinds of mechanical and electrical failures,seriously affecting the reliable and stable energy transmission of the power grid.The existing research focuses on the wind field simulation of ideal micro-terrain and actual terrain with mostly single microterrain characteristics.Model boundary constraints and the influence of constrained boundaries are the main problems that need to be solved to accurately model and simulate complex flow fields.In this paper,a flow field simulation method based on circular boundary constraints is carried out.During the study,the influence of the model boundary and the selection conditions of themodeling range are systematically analyzed.It is more suitable to make sure that the air domain is 4 times higher than the height of the hill undulations,in addition to ensuring that there should be a minimum of 400 m between the study region and the boundary.Then,an actual terrain model of a power grid line in Shanxi is established,through the method proposed in this paper,the wind speed at the location of the transmission tower line under different wind directions is analyzed,and it is found that when the incidence direction is 45 degrees north by east the wind speed is the highest.The findings demonstrate that the circular boundary model has the advantage of more easily adjusting the wind incidence direction,in addition to theoretically reducing the errors caused by traditional models in boundary processing.It can accurately obtain the distribution characteristics of the flow field affected by the terrain,and quickly screen out the extreme working conditions that are most harmful to the transmission lines in the actual transmission line for energy transmission in complex loess hilly regions.
基金supported by the National Key Research and Development Program of China(2023YFB4202503)the cooperation project between Three Gorges Corporation and Nankai University(202103571)+6 种基金the National Natural Science Foundation Joint Fund(U21A2072)the National Science Foundation(62274099,62104115)Tianjin Science and Technology Project(24ZXZSSS00160)Yunnan Provincial Science and Technology Project at Southwest United Graduate School(202302A0370009)the China Higher Education Discipline Innovation Overseas Expert Introduction Project(B16027)the Haihe Laboratory of Sustainable Chemical Transformationsthe Fundamental Research Funds for the Central Universities,Nankai University。
文摘[4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid(Me-4PACz)self-assembled monolayer(SAM)as the hole transport materials have been demonstrated remarkable potential in perovskite solar cells(PSCs).However,the hydrophobicity of Me-4PACz presents a critical challenge for the fabrication of high-quality perovskite films due to its poor wettability.Here,a doped Al_(2)O_(3)with Me-4PACz to modify the Me-4PACz surface was proposed.On one hand,this approach improved the wettability of the Me-4PACz film,enhancing the coverage,uniformity,and buried interface properties of the perovskite film.On the other hand,compared to Al_(2)O_(3)modification alone,doping Al_(2)O_(3)with Me-4PACz allowed direct contact between the perovskite and Me-4PACz,resulting in better buried interface passivation.As a result,we achieved an efficiency of 22.71%for single-junction wide-bandgap perovskite solar cells(1.68 eV).Additionally,the efficiency of perovskite/silicon tandem solar cells was improved from 28.68%to 30.92%,with a significant reduction in hysteresis.Furthermore,the tandem cells demonstrated no degradation after 4200 s of operation at the maximum power point.
