This paper suggests a group of statistical algorithms for calculating the total absorption coefficients based on in situ data of apparent optical property and inherent optical property collected with strict quality as...This paper suggests a group of statistical algorithms for calculating the total absorption coefficients based on in situ data of apparent optical property and inherent optical property collected with strict quality assurance according to NASA ocean bio-optic protocols in the Yellow Sea and the East China Sea in spring 2003. The band-ratios ofRrs412/Rrs555, Rrs49o/Rrs555 are used in the algorithms to derive the total absorption coefficients （at） at 412, 440, 488, 510, 532 and 555nm bands, respectively. The average relative errors between inversed and measured values are less than 25.8%, with the correlative coefficients （R2） being 0.75-0.85. Error sensitivity analysis shows that the maximum retrieval error is less than 24.0% at ＋5% error in Rrs＇s. So the statistical algorithms of this paper are practicable. In this paper, the relations between the total absorption coefficients at 412, 488, 510, 532, 555 nm and that of 440nm are also studied. The results show that the relations between the total absorption coefficients of 400-600 nm and that of 440 nm are correlated well and all of their correlative coefficients R2 are greater than 0.99. Furthermore, a regression analysis is also done for the slope of the linear relations and wavelengths, and the R2 is also 0.99. Thus it is possible to retrieve other bands＇ total absorption coefficients with only one band absorption value, which significantly reduce the number of unknown parameters in studying other ocean color related problems.展开更多
Temporal and spatial patterns of inherent optical properties in the Bohai Sea are very complex. In this paper, we used 77 groups of field data of AOPs （apparent optical properties） and IOPs （inherent optical proper...Temporal and spatial patterns of inherent optical properties in the Bohai Sea are very complex. In this paper, we used 77 groups of field data of AOPs （apparent optical properties） and IOPs （inherent optical properties） collected in June, August, and September of 2005 in the Bohai Sea, to retrieve the spectral total absorption coefficient a（2） with the quasi-analytical algorithm （QAA）. For QAA implementation, different bands in the region 680-730 nm （in 5 nm intervals） were selected and compared, to determine the optimal band domain of the reference wavelength. On this basis, we proposed a new algorithm （QAA-Com）, a combination of QAA-685 and QAA-715, according to turbidity characterized by a（440）. The percentage difference of model retrievals in the visible domain was between 4.5%-45.1%, in average of 18.8% for a（2）. The QAA model was then applied to Medium Resolution Imaging Spectrometer （MERIS） radiometric products, which were temporally and spatially matched with in-situ optical measurements. Differences between MERIS retrievals and in-situ values were in the range 9.2%-27.8% for a（2） in the visible domain. Major errors in satellite retrieval are attributable to uncertainties of QAA model parameters and in-situ measurements, as well as imperfect atmospheric correction of MERIS data by the European Space Agency （ESA）. During a storm surge in April 2009, time series of MERIS images together with the QAA model were used to analyze spatial and temporal variability of the total absorption coefficient pattern in the Bohai Sea. It is necessary to collect more independent field data to improve this algorithm.展开更多
Using the digisonde data observed at ionospheric station Norilsk （Dip lat. 60~N） in 2006, a statistical study on the characteristics of the ionospheric plasma total absorption of radio waves （IPTAR） was performed....Using the digisonde data observed at ionospheric station Norilsk （Dip lat. 60~N） in 2006, a statistical study on the characteristics of the ionospheric plasma total absorption of radio waves （IPTAR） was performed. In the winter and some months of equinox, the IPTAR mainly occurred in the nighttime and the highest occurrence rate could be up to 90%. In the summer, the occurrence was relatively low and the differences between nighttime and daytime occurrence reduced. The total duration of IPTAR seemed longer around the winter than that around the summer. The occurrence of IPTAR events ascended as the Kp index increased. The frequent precipitation of energetic particles into the ionospheric plasma in the auroral belt may be the main cause of the IPTAR events.展开更多
Total absorption gamma-ray spectroscopy(TAGS)is a powerful tool for measuring complexγ transitions,which has been effectively applied to the study of reactor decay heat.This paper presents the design of a new TAGS de...Total absorption gamma-ray spectroscopy(TAGS)is a powerful tool for measuring complexγ transitions,which has been effectively applied to the study of reactor decay heat.This paper presents the design of a new TAGS detector,the large-scale modular BGO detection array(LAMBDA),tailored for measuringβ-decay intensity distributions of fission products.The modular design allows the LAMBDA detectors to be assembled in various configurations.The final version of LAMBDA consists of 102 identical 60 mm×60 mm×120 mm BGO crystals and exhibits a high full-energy peak efficiency exceeding 80%at 0.5∼8 MeV based on a Monte Carlo simulation.Currently,approximately half of the LAMBDA modules have been manufactured.Tests usingγ-ray sources and nuclear reactions demonstrated favorable energy resolution,energy linearity,and efficiency uniformity across the modules.Forty-eight modules have been integrated into the prototype LAMBDA-I.The capability of LAMBDA-I inβ-delayedγ-decay experiments was evaluated by commissioning measurements using the ^(152)Eu source.展开更多
Objective To investigate the specific activities of gamma radionuclides in the soils around high energy accelerators,and to analyze the influence of rays emitted by nuclides with characteristic peaks at similar energy...Objective To investigate the specific activities of gamma radionuclides in the soils around high energy accelerators,and to analyze the influence of rays emitted by nuclides with characteristic peaks at similar energy points on nuclide measurement results,in order to provide reference for the accurate identification of radionuclides.Methods GR5021 high-purity germanium gamma spectroscopy system was used to measure the specific activities of gamma-emitting radionuclides 226Ra,232Th,238U,40K and artificial radionuclides 54Mn,52Mn,7Be,22Na,59Fe,95Zr in six soil samples around three kinds of high energy accelerators,and the theoretical counts of the characteristic peak of 835.7keV were compared with the measured counts of the characteristic peak of 54Mn.Results The specific activity ranges of gamma-emitting radionuclides 226Ra,232Th,238U and 40K in the soils around three kinds of high energy accelerators were 55.5–171,34.9–99.9,21.9–79.3 and 247–680 Bq/kg,respectively.The specific activities of artificial radionuclides 52Mn,7Be,22Na,59Fe and 95Zr were basically lower than the minimum detection limit.A characteristic peak was found at the energy point of 835.7keV in six soil samples,and the corresponding total absorption peak counts were from 228Ac of 232Thdecay daughter.Conclusions The specific activities of gamma-emitting radionuclides were at the normal natural background levels.The specific activities of artificial radionuclides were basically lower than the minimum detection limits.For 232Th,when its specific activity is above 40 Bq/kg,characteristic peak of its decay daughter 228Ac could be misjudged as characteristic peak of 54Mn.展开更多
With the combination of modern quantitative analysis method and enterprise inputoutput model,in this paper we make a scientific analysis on the effect to product profit tax from the change of internal and external imp...With the combination of modern quantitative analysis method and enterprise inputoutput model,in this paper we make a scientific analysis on the effect to product profit tax from the change of internal and external important factors of enterprise,and some important results hare been given.展开更多
The development of efficient non-precious metal catalysts is important for the large-scale application of alkaline hydrogen evolution reaction(HER).Here,we synthesized a composite catalyst of Cu and Mo_(2)C(Cu/Mo_(2)C...The development of efficient non-precious metal catalysts is important for the large-scale application of alkaline hydrogen evolution reaction(HER).Here,we synthesized a composite catalyst of Cu and Mo_(2)C(Cu/Mo_(2)C)using Anderson-type polyoxometalates(POMs)synthesized by the facile soaking method as precursors.The electronic interaction between Cu and Mo_(2)C drives the positive charge of Cu,alleviating the strong adsorption of hydrogen at the Mo site by modulating the d-band center of Mo_(2)C.By studying the interfacial water structure using in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy(ATR-SEIRAS),we determined that the positively charged Cu crystals have the function of activating water molecules and optimizing the interfacial water structure.The interfacial water of Cu/Mo_(2)C contains a large amount of free water,which could facilitate the transport of reaction intermediates.Due to activated water molecules and optimized interfacial water structure and hydrogen adsorption energy,the overpotential of Cu/Mo_(2)C is 24 mV at a current density of 10 mA·cm^(-2) and 178 mV at a current density of 1000 mA·cm^(-2).This work improves catalyst performance in terms of interfacial water structure optimization and deepens the understanding of water-mediated catalysis.展开更多
Through interface engineering and content control strategy,a PdBi bimetallic interface structure was constructed for the first time to selectively convert CO_(2)to formate with a remarkably high Faraday efficiency(FEf...Through interface engineering and content control strategy,a PdBi bimetallic interface structure was constructed for the first time to selectively convert CO_(2)to formate with a remarkably high Faraday efficiency(FEformate)of 94%and a partial current density(jformate)of 34 mA·cm^(−2)at−0.8 V vs.reversible hydrogen electrode(RHE)in an H-cell.Moreover,the PdBi interface electrocatalyst even exhibited a high current density of 180 mA·cm^(−2)with formate selectivity up to 92%in a flow cell and could steadily operate for at least 20 h.Electrochemical in-situ attenuated total reflection surface enhanced infrared absorption spectroscopy(ATR-SEIRAS)confirmed that the PdBi interface could greatly weaken the adsorption of*CO intermediates due to electronic and geometric effects.Density functional theory(DFT)calculations also established that the PdBi interface regulated the CO_(2)-to-formate pathway by reducing the energy barrier toward HCOOH and largely weakening the adsorption of*CO intermediates on the catalyst surface.This study reveals that the unique PdBi bimetallic interface can provide a novel platform to study the reaction mechanism through combining in-situ ATR-SEIRAS and DFT calculations.展开更多
基金Supported by the Subsystem of Calibration and Validation, HY-1 Ground Application System, National Satellite Ocean Application Ser-vice (NSOAS). China High-Tech "863" Project (Nos. 2001AA636010, 2002AA639160 and 2002AA639200). The Ocean Science Fund Sponsor Project for the Youth, State Oceanic Administration (No. 2005415). The Director’s Science and Technology Fund Sponsor Project for the Youth, NSOAS.
文摘This paper suggests a group of statistical algorithms for calculating the total absorption coefficients based on in situ data of apparent optical property and inherent optical property collected with strict quality assurance according to NASA ocean bio-optic protocols in the Yellow Sea and the East China Sea in spring 2003. The band-ratios ofRrs412/Rrs555, Rrs49o/Rrs555 are used in the algorithms to derive the total absorption coefficients （at） at 412, 440, 488, 510, 532 and 555nm bands, respectively. The average relative errors between inversed and measured values are less than 25.8%, with the correlative coefficients （R2） being 0.75-0.85. Error sensitivity analysis shows that the maximum retrieval error is less than 24.0% at ＋5% error in Rrs＇s. So the statistical algorithms of this paper are practicable. In this paper, the relations between the total absorption coefficients at 412, 488, 510, 532, 555 nm and that of 440nm are also studied. The results show that the relations between the total absorption coefficients of 400-600 nm and that of 440 nm are correlated well and all of their correlative coefficients R2 are greater than 0.99. Furthermore, a regression analysis is also done for the slope of the linear relations and wavelengths, and the R2 is also 0.99. Thus it is possible to retrieve other bands＇ total absorption coefficients with only one band absorption value, which significantly reduce the number of unknown parameters in studying other ocean color related problems.
基金Supported by the National Natural Science Foundation of China(Nos. 60802089,40801176,40706060)the National High Technology Research and Development Program of China(863 Program)(No. 2007AA092102)
文摘Temporal and spatial patterns of inherent optical properties in the Bohai Sea are very complex. In this paper, we used 77 groups of field data of AOPs （apparent optical properties） and IOPs （inherent optical properties） collected in June, August, and September of 2005 in the Bohai Sea, to retrieve the spectral total absorption coefficient a（2） with the quasi-analytical algorithm （QAA）. For QAA implementation, different bands in the region 680-730 nm （in 5 nm intervals） were selected and compared, to determine the optimal band domain of the reference wavelength. On this basis, we proposed a new algorithm （QAA-Com）, a combination of QAA-685 and QAA-715, according to turbidity characterized by a（440）. The percentage difference of model retrievals in the visible domain was between 4.5%-45.1%, in average of 18.8% for a（2）. The QAA model was then applied to Medium Resolution Imaging Spectrometer （MERIS） radiometric products, which were temporally and spatially matched with in-situ optical measurements. Differences between MERIS retrievals and in-situ values were in the range 9.2%-27.8% for a（2） in the visible domain. Major errors in satellite retrieval are attributable to uncertainties of QAA model parameters and in-situ measurements, as well as imperfect atmospheric correction of MERIS data by the European Space Agency （ESA）. During a storm surge in April 2009, time series of MERIS images together with the QAA model were used to analyze spatial and temporal variability of the total absorption coefficient pattern in the Bohai Sea. It is necessary to collect more independent field data to improve this algorithm.
基金supported by National Natural Science Foundation of China(No.41274146)the Specialized Research Fund for State Key Laboratories of China
文摘Using the digisonde data observed at ionospheric station Norilsk （Dip lat. 60~N） in 2006, a statistical study on the characteristics of the ionospheric plasma total absorption of radio waves （IPTAR） was performed. In the winter and some months of equinox, the IPTAR mainly occurred in the nighttime and the highest occurrence rate could be up to 90%. In the summer, the occurrence was relatively low and the differences between nighttime and daytime occurrence reduced. The total duration of IPTAR seemed longer around the winter than that around the summer. The occurrence of IPTAR events ascended as the Kp index increased. The frequent precipitation of energetic particles into the ionospheric plasma in the auroral belt may be the main cause of the IPTAR events.
基金supported by the National Key R&D Program of China (Nos. 2022YFA1603300, 2018YFA0404401, 2023YFA1606701, and 2022YFA1602301)National Natural Science Foundation of China (Nos. U1867211, 12275026, and 12222514)the CAS Light of West China Program (No. 2020-82)
文摘Total absorption gamma-ray spectroscopy(TAGS)is a powerful tool for measuring complexγ transitions,which has been effectively applied to the study of reactor decay heat.This paper presents the design of a new TAGS detector,the large-scale modular BGO detection array(LAMBDA),tailored for measuringβ-decay intensity distributions of fission products.The modular design allows the LAMBDA detectors to be assembled in various configurations.The final version of LAMBDA consists of 102 identical 60 mm×60 mm×120 mm BGO crystals and exhibits a high full-energy peak efficiency exceeding 80%at 0.5∼8 MeV based on a Monte Carlo simulation.Currently,approximately half of the LAMBDA modules have been manufactured.Tests usingγ-ray sources and nuclear reactions demonstrated favorable energy resolution,energy linearity,and efficiency uniformity across the modules.Forty-eight modules have been integrated into the prototype LAMBDA-I.The capability of LAMBDA-I inβ-delayedγ-decay experiments was evaluated by commissioning measurements using the ^(152)Eu source.
文摘Objective To investigate the specific activities of gamma radionuclides in the soils around high energy accelerators,and to analyze the influence of rays emitted by nuclides with characteristic peaks at similar energy points on nuclide measurement results,in order to provide reference for the accurate identification of radionuclides.Methods GR5021 high-purity germanium gamma spectroscopy system was used to measure the specific activities of gamma-emitting radionuclides 226Ra,232Th,238U,40K and artificial radionuclides 54Mn,52Mn,7Be,22Na,59Fe,95Zr in six soil samples around three kinds of high energy accelerators,and the theoretical counts of the characteristic peak of 835.7keV were compared with the measured counts of the characteristic peak of 54Mn.Results The specific activity ranges of gamma-emitting radionuclides 226Ra,232Th,238U and 40K in the soils around three kinds of high energy accelerators were 55.5–171,34.9–99.9,21.9–79.3 and 247–680 Bq/kg,respectively.The specific activities of artificial radionuclides 52Mn,7Be,22Na,59Fe and 95Zr were basically lower than the minimum detection limit.A characteristic peak was found at the energy point of 835.7keV in six soil samples,and the corresponding total absorption peak counts were from 228Ac of 232Thdecay daughter.Conclusions The specific activities of gamma-emitting radionuclides were at the normal natural background levels.The specific activities of artificial radionuclides were basically lower than the minimum detection limits.For 232Th,when its specific activity is above 40 Bq/kg,characteristic peak of its decay daughter 228Ac could be misjudged as characteristic peak of 54Mn.
文摘With the combination of modern quantitative analysis method and enterprise inputoutput model,in this paper we make a scientific analysis on the effect to product profit tax from the change of internal and external important factors of enterprise,and some important results hare been given.
基金supported by National Natural Science Foundation of China(Nos.52376060 and 51976081).
文摘The development of efficient non-precious metal catalysts is important for the large-scale application of alkaline hydrogen evolution reaction(HER).Here,we synthesized a composite catalyst of Cu and Mo_(2)C(Cu/Mo_(2)C)using Anderson-type polyoxometalates(POMs)synthesized by the facile soaking method as precursors.The electronic interaction between Cu and Mo_(2)C drives the positive charge of Cu,alleviating the strong adsorption of hydrogen at the Mo site by modulating the d-band center of Mo_(2)C.By studying the interfacial water structure using in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy(ATR-SEIRAS),we determined that the positively charged Cu crystals have the function of activating water molecules and optimizing the interfacial water structure.The interfacial water of Cu/Mo_(2)C contains a large amount of free water,which could facilitate the transport of reaction intermediates.Due to activated water molecules and optimized interfacial water structure and hydrogen adsorption energy,the overpotential of Cu/Mo_(2)C is 24 mV at a current density of 10 mA·cm^(-2) and 178 mV at a current density of 1000 mA·cm^(-2).This work improves catalyst performance in terms of interfacial water structure optimization and deepens the understanding of water-mediated catalysis.
基金supported by the National Natural Science Foundation of China(Nos.22003074 and 22002087)Youth Innovation Promotion Association CAS,Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials(No.2021MCIMKF03)Baoshan Iron&Steel Co.,Ltd.(Baosteel),located in Shanghai,China.
文摘Through interface engineering and content control strategy,a PdBi bimetallic interface structure was constructed for the first time to selectively convert CO_(2)to formate with a remarkably high Faraday efficiency(FEformate)of 94%and a partial current density(jformate)of 34 mA·cm^(−2)at−0.8 V vs.reversible hydrogen electrode(RHE)in an H-cell.Moreover,the PdBi interface electrocatalyst even exhibited a high current density of 180 mA·cm^(−2)with formate selectivity up to 92%in a flow cell and could steadily operate for at least 20 h.Electrochemical in-situ attenuated total reflection surface enhanced infrared absorption spectroscopy(ATR-SEIRAS)confirmed that the PdBi interface could greatly weaken the adsorption of*CO intermediates due to electronic and geometric effects.Density functional theory(DFT)calculations also established that the PdBi interface regulated the CO_(2)-to-formate pathway by reducing the energy barrier toward HCOOH and largely weakening the adsorption of*CO intermediates on the catalyst surface.This study reveals that the unique PdBi bimetallic interface can provide a novel platform to study the reaction mechanism through combining in-situ ATR-SEIRAS and DFT calculations.
