Structural health monitoring is widely utilized in outdoor environments,especially under harsh conditions,which can introduce noise into the monitoring system.Therefore,designing an effective denoising strategy to enh...Structural health monitoring is widely utilized in outdoor environments,especially under harsh conditions,which can introduce noise into the monitoring system.Therefore,designing an effective denoising strategy to enhance the performance of guided wave damage detection in noisy environments is crucial.This paper introduces a local temporal principal component analysis(PCA)reconstruction approach for denoising guided waves prior to implementing unsupervised damage detection,achieved through novel autoencoder-based reconstruction.Experimental results demonstrate that the proposed denoising method significantly enhances damage detection performance when guided waves are contaminated by noise,with SNR values ranging from 10 to-5 dB.Following the implementation of the proposed denoising approach,the AUC score can elevate from 0.65 to 0.96 when dealing with guided waves corrputed by noise at a level of-5 dB.Additionally,the paper provides guidance on selecting the appropriate number of components used in the denoising PCA reconstruction,aiding in the optimization of the damage detection in noisy conditions.展开更多
A dye-sensitized photocatalyst combining Pt-loaded TiO_(2) and Ru(Ⅱ)tris-diimine sensitizer(RuP)was constructed and its activity for photochemical hydrogen evolution was compared with that of Pt-intercalated HCa_(2)N...A dye-sensitized photocatalyst combining Pt-loaded TiO_(2) and Ru(Ⅱ)tris-diimine sensitizer(RuP)was constructed and its activity for photochemical hydrogen evolution was compared with that of Pt-intercalated HCa_(2)Nb_(3)O_(10) nanosheets.When the sacrificial donor ethylenediaminetetraacetic acid(EDTA)disodium salt dihydrate was used,RuP/Pt/TiO_(2) showed higher activity than RuP/Pt/HCa_(2)Nb_(3)O_(10).In contrast,when NaI(a reversible electron donor)was used,RuP/Pt/TiO_(2) showed little activity due to back electron transfer to the electron acceptor(I_(3)-),which was gener-ated as the oxidation product of I-.By modification with anionic polymers(sodium poly(styrenesulfonate)or sodium polymethacrylate)that could inhibit the scavenging of conduction band electrons by I_(3)-,the H_(2) production activity from aqueous NaI was improved,but it did not exceed that of RuP/Pt/HCa_(2)Nb_(3)O_(10).Transient absorption measurements showed that the rate of semiconductor-to-dye back electron transfer was slower in the case of TiO_(2) than HCa_(2)Nb_(3)O_(10),but the electron transfer reaction to I3-was much faster.These results indicate that Pt/TiO_(2) is useful for reactions with sacrificial reductants(e.g.,EDTA),where the back electron transfer reaction to the more reducible product can be neglected.However,more careful design of the catalyst will be nec-essary when a reversible electron donor is employed.展开更多
基金National Science Foundation of Zhejiang under Contract(LY23E010001)。
文摘Structural health monitoring is widely utilized in outdoor environments,especially under harsh conditions,which can introduce noise into the monitoring system.Therefore,designing an effective denoising strategy to enhance the performance of guided wave damage detection in noisy environments is crucial.This paper introduces a local temporal principal component analysis(PCA)reconstruction approach for denoising guided waves prior to implementing unsupervised damage detection,achieved through novel autoencoder-based reconstruction.Experimental results demonstrate that the proposed denoising method significantly enhances damage detection performance when guided waves are contaminated by noise,with SNR values ranging from 10 to-5 dB.Following the implementation of the proposed denoising approach,the AUC score can elevate from 0.65 to 0.96 when dealing with guided waves corrputed by noise at a level of-5 dB.Additionally,the paper provides guidance on selecting the appropriate number of components used in the denoising PCA reconstruction,aiding in the optimization of the damage detection in noisy conditions.
文摘A dye-sensitized photocatalyst combining Pt-loaded TiO_(2) and Ru(Ⅱ)tris-diimine sensitizer(RuP)was constructed and its activity for photochemical hydrogen evolution was compared with that of Pt-intercalated HCa_(2)Nb_(3)O_(10) nanosheets.When the sacrificial donor ethylenediaminetetraacetic acid(EDTA)disodium salt dihydrate was used,RuP/Pt/TiO_(2) showed higher activity than RuP/Pt/HCa_(2)Nb_(3)O_(10).In contrast,when NaI(a reversible electron donor)was used,RuP/Pt/TiO_(2) showed little activity due to back electron transfer to the electron acceptor(I_(3)-),which was gener-ated as the oxidation product of I-.By modification with anionic polymers(sodium poly(styrenesulfonate)or sodium polymethacrylate)that could inhibit the scavenging of conduction band electrons by I_(3)-,the H_(2) production activity from aqueous NaI was improved,but it did not exceed that of RuP/Pt/HCa_(2)Nb_(3)O_(10).Transient absorption measurements showed that the rate of semiconductor-to-dye back electron transfer was slower in the case of TiO_(2) than HCa_(2)Nb_(3)O_(10),but the electron transfer reaction to I3-was much faster.These results indicate that Pt/TiO_(2) is useful for reactions with sacrificial reductants(e.g.,EDTA),where the back electron transfer reaction to the more reducible product can be neglected.However,more careful design of the catalyst will be nec-essary when a reversible electron donor is employed.
