滨海湿地是连接海陆生态系统的交错过渡带,具有独特的结构和功能。它们不仅在固碳方面发挥重要作用,还为动植物种群提供关键栖息地,从而有效促进了生物多样性的维持和生态系统的健康。滨海湿地遥感作为重要的交叉学科方向,其历史可以追...滨海湿地是连接海陆生态系统的交错过渡带,具有独特的结构和功能。它们不仅在固碳方面发挥重要作用,还为动植物种群提供关键栖息地,从而有效促进了生物多样性的维持和生态系统的健康。滨海湿地遥感作为重要的交叉学科方向,其历史可以追溯到20世纪70年代。在过去的50年中,滨海湿地遥感的热点主题从分布范围、生态参量反演逐步演进到生态系统功能以及碳水循环的研究。本文以Web of Science核心合集为数据库检索滨海湿地遥感的论文成果,基于VOCviewer识别了热点研究主题,并按时间顺序划分为1989年前、1990年—1999年、2000年—2009年、2010年—2019年和2020年至今5个历史阶段。通过将研究主题与新传感器的出现相结合,揭示了滨海湿地遥感的历史演变与研究现状。对于每个研究主题,详细分析了第一篇发表的文章以及被引次数较多的文章,深入解析了各个主题的发展脉络。最后,从空间大数据环境下的分类与范围制图、生态参量的精细反演、遥感与气候变化模型以及生态服务综合遥感4个方面进行未来研究趋势的展望。本研究将为了解滨海湿地遥感历史、热点和未来发展提供借鉴,并有助于指导相关领域的研究者制定更具前瞻性和针对性的研究策略,同时为政策制定者提供科学依据,以促进滨海湿地的有效保护和可持续管理。展开更多
This study explored the coupling effects of microstructure,strain rate,and 3.5%NaCl solution on stress corrosion cracking(SCC)behaviors of low-cost Ti6411 and Ti52 titanium alloys,compared to those of marine TC4ELI an...This study explored the coupling effects of microstructure,strain rate,and 3.5%NaCl solution on stress corrosion cracking(SCC)behaviors of low-cost Ti6411 and Ti52 titanium alloys,compared to those of marine TC4ELI and Ti80 titanium alloys.Slow strain rate tensile(SSRT)tests were performed to evaluate SCC susceptibility.The SCC susceptibility index(I_(SSRT))was calculated,and the fracture morphologies were investigated to clarify the stress corrosion mechanisms.The experimental results show that the ISSRT of Ti6411 titanium alloy with a lamellar micro structure(LM)is the highest under a strain rate of 1×10^(-6)s^(-1),and the corresponding fracture mode shows a quasi-cleavage fracture with low ductility.TC4ELI alloy with an equiaxed microstructure exhibits excellent SCC resistance.However,the SCC behavior of the Ti80 alloy with a bimodal microstructure is relatively sensitive to high strain rates,and the Ti52 tube with a typical Widmanst?tten microstructure is sensitive to low strain rates.The stress corrosion mechanism can be attributed to the cyclic process of passive film rupture,anodic dissolution,and hydrogen-induced cracking due to a multifactor comprehensive interaction corresponding to specific microstructures,strain rates,and corrosive media.The LM of the Ti6411 plate allowed easy chloride penetration into the bare metal,thereby reducing the protection of the film and resulting in continuous anodic dissolution and hydrogen accumulation at the crack tip.The coupled effect of the internal hydrogen pressure and external tensile stress can easily cause crack propagation and failure under service conditions.展开更多
文摘滨海湿地是连接海陆生态系统的交错过渡带,具有独特的结构和功能。它们不仅在固碳方面发挥重要作用,还为动植物种群提供关键栖息地,从而有效促进了生物多样性的维持和生态系统的健康。滨海湿地遥感作为重要的交叉学科方向,其历史可以追溯到20世纪70年代。在过去的50年中,滨海湿地遥感的热点主题从分布范围、生态参量反演逐步演进到生态系统功能以及碳水循环的研究。本文以Web of Science核心合集为数据库检索滨海湿地遥感的论文成果,基于VOCviewer识别了热点研究主题,并按时间顺序划分为1989年前、1990年—1999年、2000年—2009年、2010年—2019年和2020年至今5个历史阶段。通过将研究主题与新传感器的出现相结合,揭示了滨海湿地遥感的历史演变与研究现状。对于每个研究主题,详细分析了第一篇发表的文章以及被引次数较多的文章,深入解析了各个主题的发展脉络。最后,从空间大数据环境下的分类与范围制图、生态参量的精细反演、遥感与气候变化模型以及生态服务综合遥感4个方面进行未来研究趋势的展望。本研究将为了解滨海湿地遥感历史、热点和未来发展提供借鉴,并有助于指导相关领域的研究者制定更具前瞻性和针对性的研究策略,同时为政策制定者提供科学依据,以促进滨海湿地的有效保护和可持续管理。
基金the financial support from the National Key R&D Program of China(No.2022YFB3705605)。
文摘This study explored the coupling effects of microstructure,strain rate,and 3.5%NaCl solution on stress corrosion cracking(SCC)behaviors of low-cost Ti6411 and Ti52 titanium alloys,compared to those of marine TC4ELI and Ti80 titanium alloys.Slow strain rate tensile(SSRT)tests were performed to evaluate SCC susceptibility.The SCC susceptibility index(I_(SSRT))was calculated,and the fracture morphologies were investigated to clarify the stress corrosion mechanisms.The experimental results show that the ISSRT of Ti6411 titanium alloy with a lamellar micro structure(LM)is the highest under a strain rate of 1×10^(-6)s^(-1),and the corresponding fracture mode shows a quasi-cleavage fracture with low ductility.TC4ELI alloy with an equiaxed microstructure exhibits excellent SCC resistance.However,the SCC behavior of the Ti80 alloy with a bimodal microstructure is relatively sensitive to high strain rates,and the Ti52 tube with a typical Widmanst?tten microstructure is sensitive to low strain rates.The stress corrosion mechanism can be attributed to the cyclic process of passive film rupture,anodic dissolution,and hydrogen-induced cracking due to a multifactor comprehensive interaction corresponding to specific microstructures,strain rates,and corrosive media.The LM of the Ti6411 plate allowed easy chloride penetration into the bare metal,thereby reducing the protection of the film and resulting in continuous anodic dissolution and hydrogen accumulation at the crack tip.The coupled effect of the internal hydrogen pressure and external tensile stress can easily cause crack propagation and failure under service conditions.
