Al-Cu-Mn-Mg合金因其优异的综合性能,被广泛应用于航空航天和轨道交通等领域。然而,该合金在铸造过程中容易出现热裂缺陷,严重影响铸件的质量和可靠性。因此,提高合金的晶粒细化效果,对于改善合金的铸造性能具有重要意义。Al-Ti-B细化...Al-Cu-Mn-Mg合金因其优异的综合性能,被广泛应用于航空航天和轨道交通等领域。然而,该合金在铸造过程中容易出现热裂缺陷,严重影响铸件的质量和可靠性。因此,提高合金的晶粒细化效果,对于改善合金的铸造性能具有重要意义。Al-Ti-B细化剂是铝合金铸造中最常用的晶粒细化剂,但不同Ti/B质量比的Al-Ti-B细化剂对晶粒细化效果及热裂机制尚未系统研究。采用X射线衍射仪(XRD)、光学显微镜(OM)、扫描电镜(SEM)和CRC(constrained rod cast)金属型约束热裂棒模具等,分析了不同Ti/B质量比的Al-Ti-B细化剂对铸造Al-Cu-Mn-Mg合金微观组织和热裂倾向性的影响。实验结果表明,4种Ti/B比的Al-Ti-B细化剂中Al_3Ti和TiB_2相的含量存在显著差异。在B含量均为0.3%(质量分数)的条件下,添加Al-3Ti-1B、Al-4Ti-1B、Al-5Ti-1B和Al-5Ti-2B的Al-5Cu-0.7Mn-0.55Mg合金的平均晶粒尺寸分别为162.07、113.73、107.81和88.00μm,对应的热裂纹倾向性指数依次为112、136、96和24。微观机制分析表明,Ti B_(2)相的含量对晶粒细化效果和热裂倾向性具有显著影响。特别是Al-5Ti-2B细化剂,在晶粒细化的同时,显著降低了合金的热裂倾向性,展现出优异的性能。展开更多
梳理国外知识隐藏相关文献,揭示知识隐藏的影响因素。基于Web of Science数据库,获取紧密相关的159篇文献,采用内容分析法,从能力、机会、动机、行为等4个方面归纳知识隐藏的研究内容。研究结果发现:知识隐藏行为受到能力因素、机会因...梳理国外知识隐藏相关文献,揭示知识隐藏的影响因素。基于Web of Science数据库,获取紧密相关的159篇文献,采用内容分析法,从能力、机会、动机、行为等4个方面归纳知识隐藏的研究内容。研究结果发现:知识隐藏行为受到能力因素、机会因素、动机因素等的影响,符合COM-B模型的规律;促进知识隐藏的关键环境因素主要包括环境压力、负面关系等;抑制知识隐藏的环境因素主要包括支持性环境、心理保障、积极动机等。研究结果证实COM-B模型可用于分析知识隐藏的行为轨迹,并提出实践启示及未来研究启示。展开更多
The development of narrow-bandgap polymer donors with complementary absorption and matched energy levels for perylene diimides(PDI)-based nonfullerene acceptors(NFAs)has received little attention.The high-lying highes...The development of narrow-bandgap polymer donors with complementary absorption and matched energy levels for perylene diimides(PDI)-based nonfullerene acceptors(NFAs)has received little attention.The high-lying highest occupied molecular orbital(HOMO)level and low degree of crystallinity of the star donor polymer PCE10 limit its application in PDI-based Organic solar cells(OSCs).In this study,two benzo[1,2-b:4,5-b′]difuran(BDF)-based narrow-bandgap polymer donors,PBDF and PBDFCl,were synthesized to improve the photovoltaic performance of PDI-based OSCs.The smaller BDF moiety with higher electronegativity endows the resulting polymers with stronger aggregation and lower HOMO energy levels.The power conversion efficiency(PCE)value of the PBDF:Ph(PDI)3-based OSCs was 7.24%,which is much higher than that of PCE10-based OSCs(6.09%).Further chlorination of the conjugated side chain elevated the PCE to 8.84%,which is 1.4 times higher than that of PCE10-based OSCs.These results demonstrate the significant contribution of designing novel narrow-bandgap polymer donors to boost the PCE of PDI-based OSCs and highlight the importance of matching the aggregation behaviors of polymeric donor materials with that of NFAs.展开更多
Background Liver ischemia/reperfusion(I/R)injury is usually caused by hepatic inflow occlusion during liver surgery,and is frequently observed during war wounds and trauma.Hepatocyte ferroptosis plays a critical role ...Background Liver ischemia/reperfusion(I/R)injury is usually caused by hepatic inflow occlusion during liver surgery,and is frequently observed during war wounds and trauma.Hepatocyte ferroptosis plays a critical role in liver I/R injury,however,it remains unclear whether this process is controlled or regulated by members of the DEAD/DExH-box helicase(DDX/DHX)family.Methods The expression of DDX/DHX family members during liver I/R injury was screened using transcriptome analysis.Hepatocyte-specific Dhx58 knockout mice were constructed,and a partial liver I/R operation was performed.Single-cell RNA sequencing(scRNA-seq)in the liver post I/R suggested enhanced ferroptosis by Dhx58hep−/−.The mRNAs and proteins associated with DExH-box helicase 58(DHX58)were screened using RNA immunoprecipitation-sequencing(RIP-seq)and IP-mass spectrometry(IP-MS).Results Excessive production of reactive oxygen species(ROS)decreased the expression of the IFN-stimulated gene Dhx58 in hepatocytes and promoted hepatic ferroptosis,while treatment using IFN-αincreased DHX58 expression and prevented ferroptosis during liver I/R injury.Mechanistically,DHX58 with RNA-binding activity constitutively associates with the mRNA of glutathione peroxidase 4(GPX4),a central ferroptosis suppressor,and recruits the m6A reader YT521-B homology domain containing 2(YTHDC2)to promote the translation of Gpx4 mRNA in an m6A-dependent manner,thus enhancing GPX4 protein levels and preventing hepatic ferroptosis.Conclusions This study provides mechanistic evidence that IFN-αstimulates DHX58 to promote the translation of m6A-modified Gpx4 mRNA,suggesting the potential clinical application of IFN-αin the prevention of hepatic ferroptosis during liver I/R injury.展开更多
文摘Al-Cu-Mn-Mg合金因其优异的综合性能,被广泛应用于航空航天和轨道交通等领域。然而,该合金在铸造过程中容易出现热裂缺陷,严重影响铸件的质量和可靠性。因此,提高合金的晶粒细化效果,对于改善合金的铸造性能具有重要意义。Al-Ti-B细化剂是铝合金铸造中最常用的晶粒细化剂,但不同Ti/B质量比的Al-Ti-B细化剂对晶粒细化效果及热裂机制尚未系统研究。采用X射线衍射仪(XRD)、光学显微镜(OM)、扫描电镜(SEM)和CRC(constrained rod cast)金属型约束热裂棒模具等,分析了不同Ti/B质量比的Al-Ti-B细化剂对铸造Al-Cu-Mn-Mg合金微观组织和热裂倾向性的影响。实验结果表明,4种Ti/B比的Al-Ti-B细化剂中Al_3Ti和TiB_2相的含量存在显著差异。在B含量均为0.3%(质量分数)的条件下,添加Al-3Ti-1B、Al-4Ti-1B、Al-5Ti-1B和Al-5Ti-2B的Al-5Cu-0.7Mn-0.55Mg合金的平均晶粒尺寸分别为162.07、113.73、107.81和88.00μm,对应的热裂纹倾向性指数依次为112、136、96和24。微观机制分析表明,Ti B_(2)相的含量对晶粒细化效果和热裂倾向性具有显著影响。特别是Al-5Ti-2B细化剂,在晶粒细化的同时,显著降低了合金的热裂倾向性,展现出优异的性能。
文摘梳理国外知识隐藏相关文献,揭示知识隐藏的影响因素。基于Web of Science数据库,获取紧密相关的159篇文献,采用内容分析法,从能力、机会、动机、行为等4个方面归纳知识隐藏的研究内容。研究结果发现:知识隐藏行为受到能力因素、机会因素、动机因素等的影响,符合COM-B模型的规律;促进知识隐藏的关键环境因素主要包括环境压力、负面关系等;抑制知识隐藏的环境因素主要包括支持性环境、心理保障、积极动机等。研究结果证实COM-B模型可用于分析知识隐藏的行为轨迹,并提出实践启示及未来研究启示。
基金supported by the National Natural Science Foundation of China(Nos.52273195 and 51973169)Young Top-notch Talent Cultivation Program of Hubei Province,Natural Science Foundation of Hubei Province(No.2022CFB097)。
文摘The development of narrow-bandgap polymer donors with complementary absorption and matched energy levels for perylene diimides(PDI)-based nonfullerene acceptors(NFAs)has received little attention.The high-lying highest occupied molecular orbital(HOMO)level and low degree of crystallinity of the star donor polymer PCE10 limit its application in PDI-based Organic solar cells(OSCs).In this study,two benzo[1,2-b:4,5-b′]difuran(BDF)-based narrow-bandgap polymer donors,PBDF and PBDFCl,were synthesized to improve the photovoltaic performance of PDI-based OSCs.The smaller BDF moiety with higher electronegativity endows the resulting polymers with stronger aggregation and lower HOMO energy levels.The power conversion efficiency(PCE)value of the PBDF:Ph(PDI)3-based OSCs was 7.24%,which is much higher than that of PCE10-based OSCs(6.09%).Further chlorination of the conjugated side chain elevated the PCE to 8.84%,which is 1.4 times higher than that of PCE10-based OSCs.These results demonstrate the significant contribution of designing novel narrow-bandgap polymer donors to boost the PCE of PDI-based OSCs and highlight the importance of matching the aggregation behaviors of polymeric donor materials with that of NFAs.
基金National Key Research and Development Program of China(2023YFC2505900)National Natural Science Foundation of China(92269204,82171755,92369106,82171749,82171811,82073184)+1 种基金Military Outstanding Youth Program(2020QN06119,01-SWK JYCJJ07,23SWAQ53)Program of Leading Talents in Shanghai,and Shanghai Shuguang Program(20SG39)。
文摘Background Liver ischemia/reperfusion(I/R)injury is usually caused by hepatic inflow occlusion during liver surgery,and is frequently observed during war wounds and trauma.Hepatocyte ferroptosis plays a critical role in liver I/R injury,however,it remains unclear whether this process is controlled or regulated by members of the DEAD/DExH-box helicase(DDX/DHX)family.Methods The expression of DDX/DHX family members during liver I/R injury was screened using transcriptome analysis.Hepatocyte-specific Dhx58 knockout mice were constructed,and a partial liver I/R operation was performed.Single-cell RNA sequencing(scRNA-seq)in the liver post I/R suggested enhanced ferroptosis by Dhx58hep−/−.The mRNAs and proteins associated with DExH-box helicase 58(DHX58)were screened using RNA immunoprecipitation-sequencing(RIP-seq)and IP-mass spectrometry(IP-MS).Results Excessive production of reactive oxygen species(ROS)decreased the expression of the IFN-stimulated gene Dhx58 in hepatocytes and promoted hepatic ferroptosis,while treatment using IFN-αincreased DHX58 expression and prevented ferroptosis during liver I/R injury.Mechanistically,DHX58 with RNA-binding activity constitutively associates with the mRNA of glutathione peroxidase 4(GPX4),a central ferroptosis suppressor,and recruits the m6A reader YT521-B homology domain containing 2(YTHDC2)to promote the translation of Gpx4 mRNA in an m6A-dependent manner,thus enhancing GPX4 protein levels and preventing hepatic ferroptosis.Conclusions This study provides mechanistic evidence that IFN-αstimulates DHX58 to promote the translation of m6A-modified Gpx4 mRNA,suggesting the potential clinical application of IFN-αin the prevention of hepatic ferroptosis during liver I/R injury.
