The escalating global issues of water scarcity and pollution emphasize the critical need for the rapid development of efficient and eco-friendly water treatment technologies.Photoelectrocatalytic technology has emerge...The escalating global issues of water scarcity and pollution emphasize the critical need for the rapid development of efficient and eco-friendly water treatment technologies.Photoelectrocatalytic technology has emerged as a promising solution for effectively degrading refractory organic pollutants in water under light conditions.This review delves into the advancements made in the field,focusing on strategies to enhance the generation of active species by modulating the micro-interface of the photoanode.Strategies,such as morphological control,element doping,introduction of surface oxygen vacancies,and construction of heterostructures,significantly improve the separation efficiency of photogenerated charges and the generation of active species,thereby boosting the efficiency of photoelectrocatalytic performance.Furthermore,the review explores the potential applications of photoelectrocatalytic technology in organic pollutant degradation in solutions.It also outlines the current challenges and future development directions.Despite its remarkable laboratory success,practical implementation of photoelectrocatalytic technology encounters obstacles related to stability,cost-effectiveness,and operational efficiency.Future investigations need to focus on optimizing the performance of photoelectrocatalytic materials and exploring strategies for upscaling their application in real water treatment scenarios.展开更多
Current research focuses on the performance degradation of photovoltaic(PV)modules,examining both crystalline silicon(p-Si and m-Si)and thin-film technologies,including a-Si/μc-Si,HIT,CdTe and CIGS.These modules were...Current research focuses on the performance degradation of photovoltaic(PV)modules,examining both crystalline silicon(p-Si and m-Si)and thin-film technologies,including a-Si/μc-Si,HIT,CdTe and CIGS.These modules were operated outdoors in two distinct climatic zones in the United States(US)over a period of three years.The degradation analysis includes the study of various quantities,such as the decrease in peak power,the reduction in current and voltage,and the variation in the fill factor.The annual degradation rate(DR)of PV modules is obtained by a linear fit of the effective maximum power evolution over time.The results indicate that m-Si and p-Si modules experienced a slight decrease in performance,with DRs of−0.83%and−1.07%,respectively.Subsequently,the HIT module exhibited a DR of−1.75%,while CdTe and CIGS modules demonstrated DRs of−2.03%and−2.45%,respectively.The a-Si/μc-Si module showed the highest DR at−3.26%.Using the Single Diode Model(SDM),we monitored the temporal evolution of physical parameters as well as changes in the shape of the I-V and P-V curves over time.We found that the key points of the I-V curve degrade over time,as do the I-V and P-V characteristics between two days approximately 30 months apart.展开更多
As one photovoltaic supernova,perovskite solar cells(PSCs)have exhibited certified power conversion efficiencies exceeding 27%.Yet,the presence of enormous defects,mainly for the dominant iodine vacancy(VI),always ind...As one photovoltaic supernova,perovskite solar cells(PSCs)have exhibited certified power conversion efficiencies exceeding 27%.Yet,the presence of enormous defects,mainly for the dominant iodine vacancy(VI),always induces nonradiative recombination,ion migration,and triggers autocatalytic iodine oxidation into volatile I_(2) and charge-localization-mediated metallic Pb0clusters,which accelerate device failure and therefore hamper commercialization.However,popularly reported strategies that simultaneously enable vacancy passivation and iodine scavenging remain insufficient,highlighting the need for new additives.Herein,we employ 4-cyanophenylhydrazine hydrochloride(CPHCl)as an iodine-related synergistic redox-coordination stabilizer to address intrinsic instability and interface chemistry issues.After systematically characterizations,we demonstrate that CPHCl not only specifically eliminates I_(2) intermediates by leveraging the redox-active hydrazine group(NH–NH_(2))(I_(2)+NH–NH_(2)→2HI+N=NH),but also passivates Pb^(2+)/FA^(+) related defects viaπ-backdonation and hydrogen bonding by the electron-donating cyano(C≡N)group,synergistically modulating the crystallization kinetics and improving the final quality of the perovskite film.As a result,vacancy-mediated I-ion migration and degradation are significantly relieved,enabling an enhanced efficiency of 25.56%for the p-i-n inverted PSC with exceptional operational stability.This work provides a deep insight into screening perovskite stabilizers for advancing toward commercial longevity.展开更多
In practical engineering construction,multi-layered barriers containing geomembranes are extensively applied to retard the migration of pollutants.However,the associated analytical theory on pollutants diffusion still...In practical engineering construction,multi-layered barriers containing geomembranes are extensively applied to retard the migration of pollutants.However,the associated analytical theory on pollutants diffusion still needs to be further improved.In this work,general analytical solutions are derived for one-dimensional diffusion of degradable organic contaminant(DOC)in the multi-layered media containing geomembranes under a time-varying concentration boundary condition,where the variable substitution and separated variable approaches are employed.These analytical solutions with clear expressions can be used not only to study the diffusion behaviors of DOC in bottom and vertical composite barrier systems,but also to verify other complex numerical models.The proposed general analytical solutions are then fully validated via three comparative analyses,including comparisons with the experimental measurements,an existing analytical solution,and a finite-difference solution.Ultimately,the influences of different factors on the composite cutoff wall’s(CCW,which consists of two soil-bentonite layers and a geomembrane)service performance are investigated through a composite vertical barrier system as the application example.The findings obtained from this investigation can provide scientific guidance for the barrier performance evaluation and the engineering design of CCWs.This application example also exhibits the necessity and effectiveness of the developed analytical solutions.展开更多
With the continuous improvement of China's science and technology, the design method of steel structure is also more and more, how to better apply the module building design method to the related buildings, is the...With the continuous improvement of China's science and technology, the design method of steel structure is also more and more, how to better apply the module building design method to the related buildings, is the current issue to focus on consideration. Therefore, this paper will focus on the design method of multi-layer steel structure module and steel frame composite building structure, and analyze and study its structure, so as to improve the utilization rate of steel structure and promote the development of the construction industry.展开更多
Photovoltaic (PV) modules, as essential components of solar power generation systems, significantly influence unitpower generation costs.The service life of these modules directly affects these costs. Over time, the p...Photovoltaic (PV) modules, as essential components of solar power generation systems, significantly influence unitpower generation costs.The service life of these modules directly affects these costs. Over time, the performanceof PV modules gradually declines due to internal degradation and external environmental factors.This cumulativedegradation impacts the overall reliability of photovoltaic power generation. This study addresses the complexdegradation process of PV modules by developing a two-stage Wiener process model. This approach accountsfor the distinct phases of degradation resulting from module aging and environmental influences. A powerdegradation model based on the two-stage Wiener process is constructed to describe individual differences inmodule degradation processes. To estimate the model parameters, a combination of the Expectation-Maximization(EM) algorithm and the Bayesian method is employed. Furthermore, the Schwarz Information Criterion (SIC) isutilized to identify critical change points in PV module degradation trajectories. To validate the universality andeffectiveness of the proposed method, a comparative analysis is conducted against other established life predictiontechniques for PV modules.展开更多
Considering that real communication signals corrupted by noise are generally nonstationary, and timefrequency distributions are especially suitable for the analysis of nonstationary signals, time-frequency distributio...Considering that real communication signals corrupted by noise are generally nonstationary, and timefrequency distributions are especially suitable for the analysis of nonstationary signals, time-frequency distributions are introduced for the modulation classification of communication signals： The extracted time-frequency features have good classification information, and they are insensitive to signal to noise ratio （SNR） variation. According to good classification by the correct rate of a neural network classifier, a multilayer perceptron （MLP） classifier with better generalization, as well as, addition of time-frequency features set for classifying six different modulation types has been proposed. Computer simulations show that the MLP classifier outperforms the decision-theoretic classifier at low SNRs, and the classification experiments for real MPSK signals verify engineering significance of the MLP classifier.展开更多
A 10 Gbit/s 16-km-long reconfigurable wavelength-division-multiplexing passive optical network(WDM-PON) is presented empowered by a low-cost multi-channel directly modulated laser(DML) module. Compared with the case u...A 10 Gbit/s 16-km-long reconfigurable wavelength-division-multiplexing passive optical network(WDM-PON) is presented empowered by a low-cost multi-channel directly modulated laser(DML) module. Compared with the case using discrete devices in conventional scheme, the proposed DML module provides a cost-effective solution with reduced complexity. The clear eye diagram and the bit error rate(BER) of less than 2×10^(-7) with a sensitivity of-7 dB m are obtained. Due to the special packaging design, the crosstalk between channels under condition of simultaneous operation can be negligible.展开更多
In order to accurately select photovoltaic modules under different climatic conditions,three kinds of polycrystalline silicon photovoltaic modules were prepared for this study using different properties of packaging m...In order to accurately select photovoltaic modules under different climatic conditions,three kinds of polycrystalline silicon photovoltaic modules were prepared for this study using different properties of packaging materials and two typical climatic zones of China were selected for installation and operation of these photovoltaic(PV)modules.The photoelectric parameters(maximum power,open-circuit voltage,short-circuit current,etc.)and electroluminescence images of these modules were analysed before and after their operation for 6 months.The study found that the performance of PV modules in different climatic regions shows different decay tendency and degradation mechanism.There was a significant difference in the degradation of the three different types of PV modules in the sub-humid-hot region(Suzhou,Jiangsu);two kinds of photovoltaic modules using relatively poorly performing package materials showed significant potential-induced degradation effects.However,the degradation trend of the three different types of PV modules in the warm-temperate region(Kenli,Shandong)was consistent and no significant potential-induced degradation effect was observed.展开更多
Nitro explosives are harmful to the ecological environment and human health and they are diffcult to eliminate.Herein,a simple and environmentally friendly citric acid modulated hydrothermal method was used to prepare...Nitro explosives are harmful to the ecological environment and human health and they are diffcult to eliminate.Herein,a simple and environmentally friendly citric acid modulated hydrothermal method was used to prepare regular square-like BiOCl nanoplates with high exposure{001}facets.The results of characterizations showed that reduced-size square-like BiOCl nanoplates were with high exposure{001}facets.Nitro explosives,including p-nitrophenol(PNP),2,4-dinitrophenol(2,4-DNP),2,4,6-trinitrophenol(2,4,6-TNP),and 2,4,6-trinitrotoluene(TNT),were selected to inquire into the catalytic properties of pre pared samples under simulated irradiation.The catalytic performance of BC-10 was the best.In particular,BC-10 could thoroughly degrade four nitro explosives solutions,namely,PNP,2,4-DNP,2,4,6-TNP,and TNT(20 mg L^(−1))under simulated irradiation in 50,90,90,and 90 min,respectively;photocatalytic mechanism was exhaustively discussed.Photoelectrochemical,in additon to electron paramagnetic reso nance characterizations,suggested that the intrinsic factor for the superior photocatalytic performance was the enhancement of the transfer and separation effciency of photogenerated charge carriers derived from the BiOCl{001}active facets.Moreover,the primary active substance in the system was superoxide radicals.This study may provide new insights on the preparation of effcient catalysts for degrading nitro explosives.展开更多
基金financially supported by the National Natural Science Foundation of China (No.52100076)the Fundamental Research Funds for the Central Universities (No.2023MS064)。
文摘The escalating global issues of water scarcity and pollution emphasize the critical need for the rapid development of efficient and eco-friendly water treatment technologies.Photoelectrocatalytic technology has emerged as a promising solution for effectively degrading refractory organic pollutants in water under light conditions.This review delves into the advancements made in the field,focusing on strategies to enhance the generation of active species by modulating the micro-interface of the photoanode.Strategies,such as morphological control,element doping,introduction of surface oxygen vacancies,and construction of heterostructures,significantly improve the separation efficiency of photogenerated charges and the generation of active species,thereby boosting the efficiency of photoelectrocatalytic performance.Furthermore,the review explores the potential applications of photoelectrocatalytic technology in organic pollutant degradation in solutions.It also outlines the current challenges and future development directions.Despite its remarkable laboratory success,practical implementation of photoelectrocatalytic technology encounters obstacles related to stability,cost-effectiveness,and operational efficiency.Future investigations need to focus on optimizing the performance of photoelectrocatalytic materials and exploring strategies for upscaling their application in real water treatment scenarios.
文摘Current research focuses on the performance degradation of photovoltaic(PV)modules,examining both crystalline silicon(p-Si and m-Si)and thin-film technologies,including a-Si/μc-Si,HIT,CdTe and CIGS.These modules were operated outdoors in two distinct climatic zones in the United States(US)over a period of three years.The degradation analysis includes the study of various quantities,such as the decrease in peak power,the reduction in current and voltage,and the variation in the fill factor.The annual degradation rate(DR)of PV modules is obtained by a linear fit of the effective maximum power evolution over time.The results indicate that m-Si and p-Si modules experienced a slight decrease in performance,with DRs of−0.83%and−1.07%,respectively.Subsequently,the HIT module exhibited a DR of−1.75%,while CdTe and CIGS modules demonstrated DRs of−2.03%and−2.45%,respectively.The a-Si/μc-Si module showed the highest DR at−3.26%.Using the Single Diode Model(SDM),we monitored the temporal evolution of physical parameters as well as changes in the shape of the I-V and P-V curves over time.We found that the key points of the I-V curve degrade over time,as do the I-V and P-V characteristics between two days approximately 30 months apart.
基金partly funded by the National Natural Science Foundation of China(62204098,62304124,62374105,22309107)Natural Science Foundation of Shandong Province(ZR2024QE036,ZR2024QB021,ZR2023QB281)+1 种基金Special Fund of Taishan Scholar Program of Shandong Province(tsqnz20221141)Qingdao Natural Science Foundation(24-4-4-zrjj-21-jch,25-1-1-114-zyydjch)。
文摘As one photovoltaic supernova,perovskite solar cells(PSCs)have exhibited certified power conversion efficiencies exceeding 27%.Yet,the presence of enormous defects,mainly for the dominant iodine vacancy(VI),always induces nonradiative recombination,ion migration,and triggers autocatalytic iodine oxidation into volatile I_(2) and charge-localization-mediated metallic Pb0clusters,which accelerate device failure and therefore hamper commercialization.However,popularly reported strategies that simultaneously enable vacancy passivation and iodine scavenging remain insufficient,highlighting the need for new additives.Herein,we employ 4-cyanophenylhydrazine hydrochloride(CPHCl)as an iodine-related synergistic redox-coordination stabilizer to address intrinsic instability and interface chemistry issues.After systematically characterizations,we demonstrate that CPHCl not only specifically eliminates I_(2) intermediates by leveraging the redox-active hydrazine group(NH–NH_(2))(I_(2)+NH–NH_(2)→2HI+N=NH),but also passivates Pb^(2+)/FA^(+) related defects viaπ-backdonation and hydrogen bonding by the electron-donating cyano(C≡N)group,synergistically modulating the crystallization kinetics and improving the final quality of the perovskite film.As a result,vacancy-mediated I-ion migration and degradation are significantly relieved,enabling an enhanced efficiency of 25.56%for the p-i-n inverted PSC with exceptional operational stability.This work provides a deep insight into screening perovskite stabilizers for advancing toward commercial longevity.
基金Project(2023YFC3707800)supported by the National Key Research and Development Program of China。
文摘In practical engineering construction,multi-layered barriers containing geomembranes are extensively applied to retard the migration of pollutants.However,the associated analytical theory on pollutants diffusion still needs to be further improved.In this work,general analytical solutions are derived for one-dimensional diffusion of degradable organic contaminant(DOC)in the multi-layered media containing geomembranes under a time-varying concentration boundary condition,where the variable substitution and separated variable approaches are employed.These analytical solutions with clear expressions can be used not only to study the diffusion behaviors of DOC in bottom and vertical composite barrier systems,but also to verify other complex numerical models.The proposed general analytical solutions are then fully validated via three comparative analyses,including comparisons with the experimental measurements,an existing analytical solution,and a finite-difference solution.Ultimately,the influences of different factors on the composite cutoff wall’s(CCW,which consists of two soil-bentonite layers and a geomembrane)service performance are investigated through a composite vertical barrier system as the application example.The findings obtained from this investigation can provide scientific guidance for the barrier performance evaluation and the engineering design of CCWs.This application example also exhibits the necessity and effectiveness of the developed analytical solutions.
文摘With the continuous improvement of China's science and technology, the design method of steel structure is also more and more, how to better apply the module building design method to the related buildings, is the current issue to focus on consideration. Therefore, this paper will focus on the design method of multi-layer steel structure module and steel frame composite building structure, and analyze and study its structure, so as to improve the utilization rate of steel structure and promote the development of the construction industry.
基金supported by the National Natural Science Foundation of China(51767017)the Basic Research Innovation Group Project of Gansu Province(18JR3RA133)the Industrial Support and Guidance Project of Universities in Gansu Province(2022CYZC-22).
文摘Photovoltaic (PV) modules, as essential components of solar power generation systems, significantly influence unitpower generation costs.The service life of these modules directly affects these costs. Over time, the performanceof PV modules gradually declines due to internal degradation and external environmental factors.This cumulativedegradation impacts the overall reliability of photovoltaic power generation. This study addresses the complexdegradation process of PV modules by developing a two-stage Wiener process model. This approach accountsfor the distinct phases of degradation resulting from module aging and environmental influences. A powerdegradation model based on the two-stage Wiener process is constructed to describe individual differences inmodule degradation processes. To estimate the model parameters, a combination of the Expectation-Maximization(EM) algorithm and the Bayesian method is employed. Furthermore, the Schwarz Information Criterion (SIC) isutilized to identify critical change points in PV module degradation trajectories. To validate the universality andeffectiveness of the proposed method, a comparative analysis is conducted against other established life predictiontechniques for PV modules.
文摘Considering that real communication signals corrupted by noise are generally nonstationary, and timefrequency distributions are especially suitable for the analysis of nonstationary signals, time-frequency distributions are introduced for the modulation classification of communication signals： The extracted time-frequency features have good classification information, and they are insensitive to signal to noise ratio （SNR） variation. According to good classification by the correct rate of a neural network classifier, a multilayer perceptron （MLP） classifier with better generalization, as well as, addition of time-frequency features set for classifying six different modulation types has been proposed. Computer simulations show that the MLP classifier outperforms the decision-theoretic classifier at low SNRs, and the classification experiments for real MPSK signals verify engineering significance of the MLP classifier.
基金supported by the National High-Tech Research and Development Program of China(No.2013AA014201)the National Natural Science Foundation of China(Nos.61575186 and 61635001)
文摘A 10 Gbit/s 16-km-long reconfigurable wavelength-division-multiplexing passive optical network(WDM-PON) is presented empowered by a low-cost multi-channel directly modulated laser(DML) module. Compared with the case using discrete devices in conventional scheme, the proposed DML module provides a cost-effective solution with reduced complexity. The clear eye diagram and the bit error rate(BER) of less than 2×10^(-7) with a sensitivity of-7 dB m are obtained. Due to the special packaging design, the crosstalk between channels under condition of simultaneous operation can be negligible.
文摘In order to accurately select photovoltaic modules under different climatic conditions,three kinds of polycrystalline silicon photovoltaic modules were prepared for this study using different properties of packaging materials and two typical climatic zones of China were selected for installation and operation of these photovoltaic(PV)modules.The photoelectric parameters(maximum power,open-circuit voltage,short-circuit current,etc.)and electroluminescence images of these modules were analysed before and after their operation for 6 months.The study found that the performance of PV modules in different climatic regions shows different decay tendency and degradation mechanism.There was a significant difference in the degradation of the three different types of PV modules in the sub-humid-hot region(Suzhou,Jiangsu);two kinds of photovoltaic modules using relatively poorly performing package materials showed significant potential-induced degradation effects.However,the degradation trend of the three different types of PV modules in the warm-temperate region(Kenli,Shandong)was consistent and no significant potential-induced degradation effect was observed.
基金support received from the Natural Science Foundation of China(21875192)Outstanding Youth Science and Technology Talents Program of Sichuan(19JCQN0085)Open Project of State Key Laboratory of Environment-friendly Energy Materials(19fksy04).
文摘Nitro explosives are harmful to the ecological environment and human health and they are diffcult to eliminate.Herein,a simple and environmentally friendly citric acid modulated hydrothermal method was used to prepare regular square-like BiOCl nanoplates with high exposure{001}facets.The results of characterizations showed that reduced-size square-like BiOCl nanoplates were with high exposure{001}facets.Nitro explosives,including p-nitrophenol(PNP),2,4-dinitrophenol(2,4-DNP),2,4,6-trinitrophenol(2,4,6-TNP),and 2,4,6-trinitrotoluene(TNT),were selected to inquire into the catalytic properties of pre pared samples under simulated irradiation.The catalytic performance of BC-10 was the best.In particular,BC-10 could thoroughly degrade four nitro explosives solutions,namely,PNP,2,4-DNP,2,4,6-TNP,and TNT(20 mg L^(−1))under simulated irradiation in 50,90,90,and 90 min,respectively;photocatalytic mechanism was exhaustively discussed.Photoelectrochemical,in additon to electron paramagnetic reso nance characterizations,suggested that the intrinsic factor for the superior photocatalytic performance was the enhancement of the transfer and separation effciency of photogenerated charge carriers derived from the BiOCl{001}active facets.Moreover,the primary active substance in the system was superoxide radicals.This study may provide new insights on the preparation of effcient catalysts for degrading nitro explosives.
