A novel cationic Pt(Ⅱ)complex 2 with 2-(2,4-difluorophenyl)pyridine as the cyclometalating ligand and 1,10-phenanthroline as the auxiliary ligand has been synthesized and fully characterized.This complex exhibits muc...A novel cationic Pt(Ⅱ)complex 2 with 2-(2,4-difluorophenyl)pyridine as the cyclometalating ligand and 1,10-phenanthroline as the auxiliary ligand has been synthesized and fully characterized.This complex exhibits much higher aggregation-induced phosphorescent emission activity than that of a nonfluorinated complex 1 in CH_(3)CN/H_(2)O.The complex 2 demonstrates efficient detection on picric acid(PA)in CH_(3)CN/H_(2)O,providing a high quenching constant(K_(SV)=2.3×10^(4) L/mol)and a low limit of detection(LOD=0.26μmol/L).In addition,complex 2 shows high selectivity for detection of PA in real water samples.Density functional theory calculations and proton nuclear magnetic resonance spectra suggest that the detection mechanism is attributed to the photo-induced electron transfer.展开更多
The utilization of hybrid energy systems has necessitated to address the various Power Quality(PQ)concerns in Distributed Generation(DG)networks.Owing to the emergence of DG networks in recent times,it is envisaged fo...The utilization of hybrid energy systems has necessitated to address the various Power Quality(PQ)concerns in Distributed Generation(DG)networks.Owing to the emergence of DG networks in recent times,it is envisaged for every utility⁃grid⁃tied system to generate and utilize harmonic⁃less electric power.Therefore,the present research critically evaluates the operation of a utility⁃grid coordinated DG system and studies its islanding operation under faulted conditions.To achieve this,an Anti⁃Islanding Protection(AIP)scheme is developed which is capable of controlling the frequency and voltage variations.This scheme is operated by a coordinated operation of multivibrators.Their operation continuously traces the pre⁃defined limits of voltage,reactive,and real power,and matches with their reference values to avoid mismatch.It is revealed that,if the mismatched values of real and reactive power exceeded its threshold value of 0.1 p.u.,then the islanding condition is detected.Especially,the proposed system is assessed in two modes:utility⁃grid and islanding modes.In utility⁃grid mode,reactive power compensation is obtained by the control of voltage and frequency signals.However,in islanding mode,the real power requirement of the connected load is obtained with reduced harmonics under unsymmetrical faulted conditions.Incremental Conductance(IC)based Maximum Power Point Tracking(MPPT)technique ensures the extraction of maximum power under varying and stochastically atmospheric conditions.Simulation results reveal that the AIP scheme promptly disconnects the utility grid from the DG network in the minimum time during dynamic variations in frequency and voltage to prevent islanding.It is justified that there is violation of the considered threshold limits even under the faulted condition.The strategy of the switchgear scheme ensures the minimum detection time of the islanding operation.Total Harmonic Distortion(THD)is 0.26%for grid voltage.It validates according to the IEEE⁃1547 standard which stipulates that the THD of grid voltage must be less than 5%.Overall,satisfactory and accurate results are obtained,which are compared with the IEEE⁃1547 standard for validation.展开更多
BACKGROUND The atherogenic index of plasma(AIP)has been shown to be positively correlated with cardiovascular disease in previous studies.However,it is unclear whether elderly people with long-term high AIP levels are...BACKGROUND The atherogenic index of plasma(AIP)has been shown to be positively correlated with cardiovascular disease in previous studies.However,it is unclear whether elderly people with long-term high AIP levels are more likely to develop coronary heart disease(CHD).Therefore,the aim of this study was to investigate the relationship between AIP trajectory and CHD incidence in elderly people.METHODS 19,194 participants aged≥60 years who had three AIP measurements between 2018 and 2020 were included in this study.AIP was defined as log10(triglyceride/high-density lipoprotein cholesterol).The group-based trajectory model was used to identify different trajectory patterns of AIP from 2018 to 2020.Cox proportional hazards models were used to estimate the hazard ratio(HR)with 95%CI of CHD events between different trajectory groups from 2020 to 2023.RESULTS Three different trajectory patterns were identified through group-based trajectory model:the low-level group(n=7410,mean AIP:-0.25 to-0.17),the medium-level group(n=9981,mean AIP:0.02-0.08),and the high-level group(n=1803,mean AIP:0.38-0.42).During a mean follow-up of 2.65 years,a total of 1391 participants developed CHD.After adjusting for potential confounders,compared with the participants in the low-level group,the HR with 95%CI of the medium-level group and the high-level group were estimated to be 1.24(1.10-1.40)and 1.43(1.19-1.73),respectively.These findings remained consistent in subgroup analyses and sensitivity analyses.CONCLUSIONS There was a significant correlation between persistent high AIP level and increased CHD risk in the elderly.This suggests that monitoring the long-term changes in AIP is helpful to identify individuals at high CHD risk in elderly people.展开更多
基金financial support from the National Natural Science Foundation of China(No.21978042)the Fundamental Research Funds for the Central Universities(No.DUT22LAB610).
文摘A novel cationic Pt(Ⅱ)complex 2 with 2-(2,4-difluorophenyl)pyridine as the cyclometalating ligand and 1,10-phenanthroline as the auxiliary ligand has been synthesized and fully characterized.This complex exhibits much higher aggregation-induced phosphorescent emission activity than that of a nonfluorinated complex 1 in CH_(3)CN/H_(2)O.The complex 2 demonstrates efficient detection on picric acid(PA)in CH_(3)CN/H_(2)O,providing a high quenching constant(K_(SV)=2.3×10^(4) L/mol)and a low limit of detection(LOD=0.26μmol/L).In addition,complex 2 shows high selectivity for detection of PA in real water samples.Density functional theory calculations and proton nuclear magnetic resonance spectra suggest that the detection mechanism is attributed to the photo-induced electron transfer.
文摘The utilization of hybrid energy systems has necessitated to address the various Power Quality(PQ)concerns in Distributed Generation(DG)networks.Owing to the emergence of DG networks in recent times,it is envisaged for every utility⁃grid⁃tied system to generate and utilize harmonic⁃less electric power.Therefore,the present research critically evaluates the operation of a utility⁃grid coordinated DG system and studies its islanding operation under faulted conditions.To achieve this,an Anti⁃Islanding Protection(AIP)scheme is developed which is capable of controlling the frequency and voltage variations.This scheme is operated by a coordinated operation of multivibrators.Their operation continuously traces the pre⁃defined limits of voltage,reactive,and real power,and matches with their reference values to avoid mismatch.It is revealed that,if the mismatched values of real and reactive power exceeded its threshold value of 0.1 p.u.,then the islanding condition is detected.Especially,the proposed system is assessed in two modes:utility⁃grid and islanding modes.In utility⁃grid mode,reactive power compensation is obtained by the control of voltage and frequency signals.However,in islanding mode,the real power requirement of the connected load is obtained with reduced harmonics under unsymmetrical faulted conditions.Incremental Conductance(IC)based Maximum Power Point Tracking(MPPT)technique ensures the extraction of maximum power under varying and stochastically atmospheric conditions.Simulation results reveal that the AIP scheme promptly disconnects the utility grid from the DG network in the minimum time during dynamic variations in frequency and voltage to prevent islanding.It is justified that there is violation of the considered threshold limits even under the faulted condition.The strategy of the switchgear scheme ensures the minimum detection time of the islanding operation.Total Harmonic Distortion(THD)is 0.26%for grid voltage.It validates according to the IEEE⁃1547 standard which stipulates that the THD of grid voltage must be less than 5%.Overall,satisfactory and accurate results are obtained,which are compared with the IEEE⁃1547 standard for validation.
基金supported by the National Key Research and Development Program of China(2017YFC1307705).
文摘BACKGROUND The atherogenic index of plasma(AIP)has been shown to be positively correlated with cardiovascular disease in previous studies.However,it is unclear whether elderly people with long-term high AIP levels are more likely to develop coronary heart disease(CHD).Therefore,the aim of this study was to investigate the relationship between AIP trajectory and CHD incidence in elderly people.METHODS 19,194 participants aged≥60 years who had three AIP measurements between 2018 and 2020 were included in this study.AIP was defined as log10(triglyceride/high-density lipoprotein cholesterol).The group-based trajectory model was used to identify different trajectory patterns of AIP from 2018 to 2020.Cox proportional hazards models were used to estimate the hazard ratio(HR)with 95%CI of CHD events between different trajectory groups from 2020 to 2023.RESULTS Three different trajectory patterns were identified through group-based trajectory model:the low-level group(n=7410,mean AIP:-0.25 to-0.17),the medium-level group(n=9981,mean AIP:0.02-0.08),and the high-level group(n=1803,mean AIP:0.38-0.42).During a mean follow-up of 2.65 years,a total of 1391 participants developed CHD.After adjusting for potential confounders,compared with the participants in the low-level group,the HR with 95%CI of the medium-level group and the high-level group were estimated to be 1.24(1.10-1.40)and 1.43(1.19-1.73),respectively.These findings remained consistent in subgroup analyses and sensitivity analyses.CONCLUSIONS There was a significant correlation between persistent high AIP level and increased CHD risk in the elderly.This suggests that monitoring the long-term changes in AIP is helpful to identify individuals at high CHD risk in elderly people.
