Crystal violet(CV)as a cationic dye shows both biological toxicity and strong visual contamination.Therefore,the detection and removal of CV are essential for the ecosystem and human health.Unfortunately,most studies ...Crystal violet(CV)as a cationic dye shows both biological toxicity and strong visual contamination.Therefore,the detection and removal of CV are essential for the ecosystem and human health.Unfortunately,most studies on this have been discrete,making it difficult to combine detection and removal in a single material.Herein,we have used 2-mercaptoacetic acid via the thiol-ene reaction for the first time to graft a carboxyl group onto a covalent organic framework(COF-A),which is capable of fluorescence detection,greatly improving the removal of CV from aqueous solution.Surprisingly,the modification also slightly improves the fluorescence detection ability.Compared with COF-A,the detec-tion limit of COF-S-COOH for CV decreased from 0.089 to 0.030μM,while the removal rate was enhanced to>99%at a concentration less than 20 mg mL^(−1).Meanwhile,COF-S-COOH has good cycling ability in both functions.These phenomena are demonstrated by instrumental characterization and theoretical calculations,revealing fluorescence quenching induced by IFE and FRET and removal effects induced by electrostatic gravity,hydrogen bonding andπ-πstacking.In this paper,we provide a new modification strategy for COF-A to achieve a bifunctional combination of detection and adsorption of CV.展开更多
在超声衍射时差(time of flight diffraction,TOFD)法检测获取的回波中,作为固定存在的侧向直通波信号会导致近表面缺陷信号不易于识别.针对这一问题,提出一种基于自适应滤波技术的杂波信号抑制方法.该方法通过迭代滤波器自身参数,调节...在超声衍射时差(time of flight diffraction,TOFD)法检测获取的回波中,作为固定存在的侧向直通波信号会导致近表面缺陷信号不易于识别.针对这一问题,提出一种基于自适应滤波技术的杂波信号抑制方法.该方法通过迭代滤波器自身参数,调节参考信号以满足待处理回波中杂波的时基抖动变化要求,并予以去除,从而分离出与其混叠的近表面缺陷信号.阐明了基于自适应滤波技术的杂波信号抑制原理,并利用所提方法对计算机仿真信号及人工缺陷检测回波进行了杂波抑制处理.结果表明,所提方法可有效滤除超声TOFD法检测回波中具有时基抖动特性的杂波信号,并提取近表面缺陷信号.展开更多
基金upported by the National Natural Science Foundation of China(21971194 and 22375150)the Developing Science Funds of Tongji University(1380219059)。
文摘Crystal violet(CV)as a cationic dye shows both biological toxicity and strong visual contamination.Therefore,the detection and removal of CV are essential for the ecosystem and human health.Unfortunately,most studies on this have been discrete,making it difficult to combine detection and removal in a single material.Herein,we have used 2-mercaptoacetic acid via the thiol-ene reaction for the first time to graft a carboxyl group onto a covalent organic framework(COF-A),which is capable of fluorescence detection,greatly improving the removal of CV from aqueous solution.Surprisingly,the modification also slightly improves the fluorescence detection ability.Compared with COF-A,the detec-tion limit of COF-S-COOH for CV decreased from 0.089 to 0.030μM,while the removal rate was enhanced to>99%at a concentration less than 20 mg mL^(−1).Meanwhile,COF-S-COOH has good cycling ability in both functions.These phenomena are demonstrated by instrumental characterization and theoretical calculations,revealing fluorescence quenching induced by IFE and FRET and removal effects induced by electrostatic gravity,hydrogen bonding andπ-πstacking.In this paper,we provide a new modification strategy for COF-A to achieve a bifunctional combination of detection and adsorption of CV.
文摘在超声衍射时差(time of flight diffraction,TOFD)法检测获取的回波中,作为固定存在的侧向直通波信号会导致近表面缺陷信号不易于识别.针对这一问题,提出一种基于自适应滤波技术的杂波信号抑制方法.该方法通过迭代滤波器自身参数,调节参考信号以满足待处理回波中杂波的时基抖动变化要求,并予以去除,从而分离出与其混叠的近表面缺陷信号.阐明了基于自适应滤波技术的杂波信号抑制原理,并利用所提方法对计算机仿真信号及人工缺陷检测回波进行了杂波抑制处理.结果表明,所提方法可有效滤除超声TOFD法检测回波中具有时基抖动特性的杂波信号,并提取近表面缺陷信号.
