The influence of combined total ionization dose(TID)and radiated electromagnetic interference(EMI)in a commercial analog-to-digital converter(ADC)was studied.The degradation of the direct-current response,the static p...The influence of combined total ionization dose(TID)and radiated electromagnetic interference(EMI)in a commercial analog-to-digital converter(ADC)was studied.The degradation of the direct-current response,the static parameters,and the dynamic parameters caused by the TID and EMI separately and synergistically is presented.The experimental results demonstrate that the increase in TID intensifies data error and the signal-tonoise ratio(SNR)degradation caused by radiated EMI.The cumulative distribution function of EMI failure with respect to data error and SNR with different TIDs was extracted.The decreasing trend of the threshold was acquired with a small sample size of five for each TID group.The result indicates that the ADC is more sensitive in a compound radiation environment.展开更多
Short-chain chlorinated paraffins(SCCPs) are still controversial candidates for inclusion in the Stockholm Convention.The inherent mixture nature of SCCPs makes it rather difficult to explore their environmental beh...Short-chain chlorinated paraffins(SCCPs) are still controversial candidates for inclusion in the Stockholm Convention.The inherent mixture nature of SCCPs makes it rather difficult to explore their environmental behaviors.A virtual molecule library of 42,720 C10-SCCP congeners covering the full structure spectrum was constructed.We explored the structural effects on the thermodynamic parameters and environmental degradability of C10-SCCPs through semi-empirical quantum chemical calculations.The thermodynamic properties were acquired using the AM1 method,and frontier molecular orbital analysis was carried out to obtain the EHOMO,ELUMO and ELUMO-EHOMO for degradability exploration at the same level.The influence of the chlorination degree(NCl on the relative stability and environmental degradation was elucidated.A novel structural descriptor,μ,was proposed to measure the dispersion of the chlorine atoms within a molecule.There were significant correlations between thermodynamic values and NCl,while the reported NCl-dependent pollution profile of C10-SCCPs in environmental samples was basically consistent with the predicted order of formation stability of C10-SCCP congeners.In addition,isomers with largeμ showed higher relative stability than those with small μ.This could be further verified by the relationship between μ and the reactivity of nucleophilic substitution and · OH attack respectively.The C10-SCCP congeners with less Cl substitution and lower dispersion degree are susceptible to environmental degradation via nucleophilic substitution and hydroxyl radical attack,while direct photolysis of C10-SCCP congeners cannot readily occur due to the large ELUMO-EHOMO values.The chlorination effect and the conclusions were further checked with appropriate density functional theory(DFT) calculations.展开更多
Continuous landscape components along the lateral riverside are affected by both hydrologic connectivity and disconnectivity.In recent years,anthropogenic activities and climate changes have caused wetland shrinkage a...Continuous landscape components along the lateral riverside are affected by both hydrologic connectivity and disconnectivity.In recent years,anthropogenic activities and climate changes have caused wetland shrinkage and land degradation along the lateral riverside of many arid and semiarid regions.Since microorganisms are major drivers of soil biochemical cycling,it is essential to examine soil microbial communities along the lateral landscape continuum to understand their ecosystem functioning and predict future land changes.Here,we collected samples along a lateral riverbed center-riverbed edge-oxbow lake-floodplain-terrace continuum(i.e.,landward distribution)in the Xilin River Basin,Inner Mongolia,China.The floodplain had the highest microbial diversity and heterogeneity,with Bacteroidetes,β-andγ-Proteobacteria being the most abundant taxa.In contrast,the terrace had the lowest microbial diversity and heterogeneity,with Acidobacteria,Actinobacteria,Verrucomicrobia,Gemmatimonadetes,andα-Proteobacteria as the most abundant taxa.Silt particle,salinity,and moisture were the most influential factors for landward variation of bacterial communities along the riverside continuum.Altogether,we demonstrate that dominant bacterial lineages,soil particles,and moisture-related factors are valuable indicators of this continuum,which can be leveraged for the early prediction of drought-induced wetland shrinkage and grassland desertification.展开更多
文摘The influence of combined total ionization dose(TID)and radiated electromagnetic interference(EMI)in a commercial analog-to-digital converter(ADC)was studied.The degradation of the direct-current response,the static parameters,and the dynamic parameters caused by the TID and EMI separately and synergistically is presented.The experimental results demonstrate that the increase in TID intensifies data error and the signal-tonoise ratio(SNR)degradation caused by radiated EMI.The cumulative distribution function of EMI failure with respect to data error and SNR with different TIDs was extracted.The decreasing trend of the threshold was acquired with a small sample size of five for each TID group.The result indicates that the ADC is more sensitive in a compound radiation environment.
基金jointly supported by the Chinese Academy of Sciences (Nos. KZCX2-YW-BR-25, XDB14030500 and YSW2013B01)the National High Technology Research and Development Program (863) of China (No. 2013AA065201)
文摘Short-chain chlorinated paraffins(SCCPs) are still controversial candidates for inclusion in the Stockholm Convention.The inherent mixture nature of SCCPs makes it rather difficult to explore their environmental behaviors.A virtual molecule library of 42,720 C10-SCCP congeners covering the full structure spectrum was constructed.We explored the structural effects on the thermodynamic parameters and environmental degradability of C10-SCCPs through semi-empirical quantum chemical calculations.The thermodynamic properties were acquired using the AM1 method,and frontier molecular orbital analysis was carried out to obtain the EHOMO,ELUMO and ELUMO-EHOMO for degradability exploration at the same level.The influence of the chlorination degree(NCl on the relative stability and environmental degradation was elucidated.A novel structural descriptor,μ,was proposed to measure the dispersion of the chlorine atoms within a molecule.There were significant correlations between thermodynamic values and NCl,while the reported NCl-dependent pollution profile of C10-SCCPs in environmental samples was basically consistent with the predicted order of formation stability of C10-SCCP congeners.In addition,isomers with largeμ showed higher relative stability than those with small μ.This could be further verified by the relationship between μ and the reactivity of nucleophilic substitution and · OH attack respectively.The C10-SCCP congeners with less Cl substitution and lower dispersion degree are susceptible to environmental degradation via nucleophilic substitution and hydroxyl radical attack,while direct photolysis of C10-SCCP congeners cannot readily occur due to the large ELUMO-EHOMO values.The chlorination effect and the conclusions were further checked with appropriate density functional theory(DFT) calculations.
基金the National Natural Science Foundation of China to J.Yu(41361053),X.Tanggood(31660724)and Y.Yang(41825016)the Natural Science Foundation of Inner Mongolia to J.Yu(2011MS0603,2016MS0331)and X.Tanggood(2015MS0306)the National College Students Innovation and Entrepreneurship Training Program of Inner Mongolia University to C.H.Li,X.Li,W.Z.Wu,W.Dong and Y.Jia(201810126043).
文摘Continuous landscape components along the lateral riverside are affected by both hydrologic connectivity and disconnectivity.In recent years,anthropogenic activities and climate changes have caused wetland shrinkage and land degradation along the lateral riverside of many arid and semiarid regions.Since microorganisms are major drivers of soil biochemical cycling,it is essential to examine soil microbial communities along the lateral landscape continuum to understand their ecosystem functioning and predict future land changes.Here,we collected samples along a lateral riverbed center-riverbed edge-oxbow lake-floodplain-terrace continuum(i.e.,landward distribution)in the Xilin River Basin,Inner Mongolia,China.The floodplain had the highest microbial diversity and heterogeneity,with Bacteroidetes,β-andγ-Proteobacteria being the most abundant taxa.In contrast,the terrace had the lowest microbial diversity and heterogeneity,with Acidobacteria,Actinobacteria,Verrucomicrobia,Gemmatimonadetes,andα-Proteobacteria as the most abundant taxa.Silt particle,salinity,and moisture were the most influential factors for landward variation of bacterial communities along the riverside continuum.Altogether,we demonstrate that dominant bacterial lineages,soil particles,and moisture-related factors are valuable indicators of this continuum,which can be leveraged for the early prediction of drought-induced wetland shrinkage and grassland desertification.