Forecasting uncertainties among meteorological fields have long been recognized as the main limitation on the accuracy and predictability of air quality forecasts.However,the particular impact of meteorological foreca...Forecasting uncertainties among meteorological fields have long been recognized as the main limitation on the accuracy and predictability of air quality forecasts.However,the particular impact of meteorological forecasting uncertainties on air quality forecasts specific to different seasons is still not well known.In this study,a series of forecasts with different forecast lead times for January,April,July,and October of 2018 are conducted over the Beijing-Tianjin-Hebei(BTH)region and the impacts of meteorological forecasting uncertainties on surface PM_(2.5)concentration forecasts with each lead time are investigated.With increased lead time,the forecasted PM_(2.5)concentrations significantly change and demonstrate obvious seasonal variations.In general,the forecasting uncertainties in monthly mean surface PM_(2.5)concentrations in the BTH region due to lead time are the largest(80%)in spring,followed by autumn(~50%),summer(~40%),and winter(20%).In winter,the forecasting uncertainties in total surface PM_(2.5)mass due to lead time are mainly due to the uncertainties in PBL heights and hence the PBL mixing of anthropogenic primary particles.In spring,the forecasting uncertainties are mainly from the impacts of lead time on lower-tropospheric northwesterly winds,thereby further enhancing the condensation production of anthropogenic secondary particles by the long-range transport of natural dust.In summer,the forecasting uncertainties result mainly from the decrease in dry and wet deposition rates,which are associated with the reduction of near-surface wind speed and precipitation rate.In autumn,the forecasting uncertainties arise mainly from the change in the transport of remote natural dust and anthropogenic particles,which is associated with changes in the large-scale circulation.展开更多
Three-dimensional(3D)modeling is an important topic in computer graphics and computer vision.In recent years,the introduction of consumer-grade depth cameras has resulted in profound advances in 3D modeling.Starting w...Three-dimensional(3D)modeling is an important topic in computer graphics and computer vision.In recent years,the introduction of consumer-grade depth cameras has resulted in profound advances in 3D modeling.Starting with the basic data structure,this survey reviews the latest developments of 3D modeling based on depth cameras,including research works on camera tracking,3D object and scene reconstruction,and high-quality texture reconstruction.We also discuss the future work and possible solutions for 3D modeling based on the depth camera.展开更多
The development of highly efficient,solution-processable,and environmentally stable perovskite quantum dots(PQDs)is crucial for their accurate high-resolution patterning and subsequently enabling the practical deploym...The development of highly efficient,solution-processable,and environmentally stable perovskite quantum dots(PQDs)is crucial for their accurate high-resolution patterning and subsequently enabling the practical deployment of PQD based emissive display devices.This study presents an innovative strategy for integrating all-inorganic PQDs and ultraviolet(UV)crosslinkable acrylate polymer at a structural and functional level.The achievement is accomplished by meticulous design and one-pot synthesis of UV-crosslinkable CsPbX_(3)(X=Cl,Br,I)PQDs solution,which exhibit outstanding environmental stability.Leveraging the solution-processable characteristics of the resulting UV-crosslinkable PQDs,precise patterning of high-resolution(2μm,7608 pixels·in.^(-1))and colorful PQDs microarrays can be readily achieved through inkjet printing and high-throughput photolithography(~2μm in pitch line/space patterning).The UV cross-linked process guarantees a homogeneous distribution of PQDs,effectively mitigating coffee ring effect and improving the overall quality of stereoscopic microarrays.The photo-cured PQDs film,which undergoes free radical photopolymerization,displays an impressive photoluminescence quantum yield(PL QY)of up to 89.2%,reaching 98%of the value observed in the solution state.The approach outlined in this research is both cost-effective and pragmatic,exhibiting tremendous promise for diverse system-level integrated optoelectronic devices,such as ultra-high-resolution micro-light-emitting device(micro-LED)displays.展开更多
The selective hydrogenation of C≡C to C=C bonds is an important step,yet remains to be a great challenge in chemical industry.In this study,we have revealed the influence of Pd deposition pH value on the catalytic pe...The selective hydrogenation of C≡C to C=C bonds is an important step,yet remains to be a great challenge in chemical industry.In this study,we have revealed the influence of Pd deposition pH value on the catalytic performance of Pd-CuO/SiO_(2)catalyst for the semi-hydrogenation of 2-methyl-3-butyn-2-ol(MBY).Trace amount of Pd(about 500 ppm)was loaded via deposition-reduction method on CuO/SiO_(2)support by using H_(2)PdCl_(4) solution as precursor and NaBH_(4)as reductant,respectively.The pH value at which Pd was deposited was adjusted to about 5 and 7 by adding NaOH solution.The obtained catalysts were characterized by several techniques including XRD,TEM,H_(2)-TPR,etc.In the case of pH value of 5,the CuO was partially dissolved during the deposition and then co-reduced with Pd^(2+)by NaBH_(4),forming PdCu alloy structure in sub-nanometer.In contrast,no PdCu alloy structure was observed when pH value was 7.The kinetics of MBY semi-hydrogenation over both catalysts were compared.The former PdCu alloy catalyst showed very high selectivity towards the semi-hydrogenation of MBY due to its low activity in hydrogenation of C=C bond in 2-methyl-3-buten-2-ol(MBE).The results herein demonstrated that the pH value where Pd was deposited played a crucial role in determining the catalytic performance of PdCu catalyst.展开更多
The general availability growth models for large scale complicated repairable system such as electric generating units, power station auxiliaries, and transmission and distribution installations are presented. The cal...The general availability growth models for large scale complicated repairable system such as electric generating units, power station auxiliaries, and transmission and distribution installations are presented. The calculation formulas for the maintenance coefficient, mathematical expressions for general availability growth models, ways for estimating, and fitting on checking the parameters of the model are introduced. Availability growth models for electric generating units, power station auxiliaries, and transmission and distribution installations are given together with verification examples for availability growth models of 320–1000 MW nuclear power units and 1000 MW thermal power units, 200–1000 MW power station auxiliaries, and 220–500 kV transmission and distribution installations. The verification results for operation availability data show that the maintenance coefficients for electric generating units, power station auxiliaries, transmission and distribution installations conform to the power function, and general availability growth models conform to rules of availability growth tendency of power equipment.展开更多
Dear Editor,Methamphetamine(METH)is a highly addictive central nervous system stimulant that has severe physical and psychological side-effects,including loss of appetite,hyperactivity,dysphoria,and depression[1].Due ...Dear Editor,Methamphetamine(METH)is a highly addictive central nervous system stimulant that has severe physical and psychological side-effects,including loss of appetite,hyperactivity,dysphoria,and depression[1].Due to its illegal production,distribution,sale,and possession it has become a worldwide burden.METH is directly toxic to dopaminergic and serotoninergic neurons,resulting in excitotoxicity,oxidative stress,and other processes[2].Research on biomolecules associated with these processes will be useful for identifying potential markers,exploring the mechanism of METH dependence,and even developing prevention and treatment strategies.展开更多
基金supported by the National Key Research and Development Program of China(No.2022YFC3700701)National Natural Science Foundation of China(Grant Nos.41775146,42061134009)+1 种基金USTC Research Funds of the Double First-Class Initiative(YD2080002007)Strategic Priority Research Program of Chinese Academy of Sciences(XDB41000000).
文摘Forecasting uncertainties among meteorological fields have long been recognized as the main limitation on the accuracy and predictability of air quality forecasts.However,the particular impact of meteorological forecasting uncertainties on air quality forecasts specific to different seasons is still not well known.In this study,a series of forecasts with different forecast lead times for January,April,July,and October of 2018 are conducted over the Beijing-Tianjin-Hebei(BTH)region and the impacts of meteorological forecasting uncertainties on surface PM_(2.5)concentration forecasts with each lead time are investigated.With increased lead time,the forecasted PM_(2.5)concentrations significantly change and demonstrate obvious seasonal variations.In general,the forecasting uncertainties in monthly mean surface PM_(2.5)concentrations in the BTH region due to lead time are the largest(80%)in spring,followed by autumn(~50%),summer(~40%),and winter(20%).In winter,the forecasting uncertainties in total surface PM_(2.5)mass due to lead time are mainly due to the uncertainties in PBL heights and hence the PBL mixing of anthropogenic primary particles.In spring,the forecasting uncertainties are mainly from the impacts of lead time on lower-tropospheric northwesterly winds,thereby further enhancing the condensation production of anthropogenic secondary particles by the long-range transport of natural dust.In summer,the forecasting uncertainties result mainly from the decrease in dry and wet deposition rates,which are associated with the reduction of near-surface wind speed and precipitation rate.In autumn,the forecasting uncertainties arise mainly from the change in the transport of remote natural dust and anthropogenic particles,which is associated with changes in the large-scale circulation.
基金National Natural Science Foundation of China(61732016).
文摘Three-dimensional(3D)modeling is an important topic in computer graphics and computer vision.In recent years,the introduction of consumer-grade depth cameras has resulted in profound advances in 3D modeling.Starting with the basic data structure,this survey reviews the latest developments of 3D modeling based on depth cameras,including research works on camera tracking,3D object and scene reconstruction,and high-quality texture reconstruction.We also discuss the future work and possible solutions for 3D modeling based on the depth camera.
基金the Research Project of Mindu Innovation Laboratory(No.2021ZZ114)the Natural Science Foundation of Xiamen(No.3502Z20227255)the Science and Technology Major Project of Fujian Province(No.2021HZ021013).
文摘The development of highly efficient,solution-processable,and environmentally stable perovskite quantum dots(PQDs)is crucial for their accurate high-resolution patterning and subsequently enabling the practical deployment of PQD based emissive display devices.This study presents an innovative strategy for integrating all-inorganic PQDs and ultraviolet(UV)crosslinkable acrylate polymer at a structural and functional level.The achievement is accomplished by meticulous design and one-pot synthesis of UV-crosslinkable CsPbX_(3)(X=Cl,Br,I)PQDs solution,which exhibit outstanding environmental stability.Leveraging the solution-processable characteristics of the resulting UV-crosslinkable PQDs,precise patterning of high-resolution(2μm,7608 pixels·in.^(-1))and colorful PQDs microarrays can be readily achieved through inkjet printing and high-throughput photolithography(~2μm in pitch line/space patterning).The UV cross-linked process guarantees a homogeneous distribution of PQDs,effectively mitigating coffee ring effect and improving the overall quality of stereoscopic microarrays.The photo-cured PQDs film,which undergoes free radical photopolymerization,displays an impressive photoluminescence quantum yield(PL QY)of up to 89.2%,reaching 98%of the value observed in the solution state.The approach outlined in this research is both cost-effective and pragmatic,exhibiting tremendous promise for diverse system-level integrated optoelectronic devices,such as ultra-high-resolution micro-light-emitting device(micro-LED)displays.
基金the financial support from the National Natural Science Foundation of China(No.21773067)the Open Research fund of Shanghai Key Laboratory of Green Chemistry and Chemical Processes。
文摘The selective hydrogenation of C≡C to C=C bonds is an important step,yet remains to be a great challenge in chemical industry.In this study,we have revealed the influence of Pd deposition pH value on the catalytic performance of Pd-CuO/SiO_(2)catalyst for the semi-hydrogenation of 2-methyl-3-butyn-2-ol(MBY).Trace amount of Pd(about 500 ppm)was loaded via deposition-reduction method on CuO/SiO_(2)support by using H_(2)PdCl_(4) solution as precursor and NaBH_(4)as reductant,respectively.The pH value at which Pd was deposited was adjusted to about 5 and 7 by adding NaOH solution.The obtained catalysts were characterized by several techniques including XRD,TEM,H_(2)-TPR,etc.In the case of pH value of 5,the CuO was partially dissolved during the deposition and then co-reduced with Pd^(2+)by NaBH_(4),forming PdCu alloy structure in sub-nanometer.In contrast,no PdCu alloy structure was observed when pH value was 7.The kinetics of MBY semi-hydrogenation over both catalysts were compared.The former PdCu alloy catalyst showed very high selectivity towards the semi-hydrogenation of MBY due to its low activity in hydrogenation of C=C bond in 2-methyl-3-buten-2-ol(MBE).The results herein demonstrated that the pH value where Pd was deposited played a crucial role in determining the catalytic performance of PdCu catalyst.
文摘The general availability growth models for large scale complicated repairable system such as electric generating units, power station auxiliaries, and transmission and distribution installations are presented. The calculation formulas for the maintenance coefficient, mathematical expressions for general availability growth models, ways for estimating, and fitting on checking the parameters of the model are introduced. Availability growth models for electric generating units, power station auxiliaries, and transmission and distribution installations are given together with verification examples for availability growth models of 320–1000 MW nuclear power units and 1000 MW thermal power units, 200–1000 MW power station auxiliaries, and 220–500 kV transmission and distribution installations. The verification results for operation availability data show that the maintenance coefficients for electric generating units, power station auxiliaries, transmission and distribution installations conform to the power function, and general availability growth models conform to rules of availability growth tendency of power equipment.
基金the National Natural Science Foundation of China(81801364 and 81571354)the China Postdoctoral Science Foundation(2018M631277)the Huayi Technology Innovation Center for Research Resources(HTIC P01 RR2018001M)。
文摘Dear Editor,Methamphetamine(METH)is a highly addictive central nervous system stimulant that has severe physical and psychological side-effects,including loss of appetite,hyperactivity,dysphoria,and depression[1].Due to its illegal production,distribution,sale,and possession it has become a worldwide burden.METH is directly toxic to dopaminergic and serotoninergic neurons,resulting in excitotoxicity,oxidative stress,and other processes[2].Research on biomolecules associated with these processes will be useful for identifying potential markers,exploring the mechanism of METH dependence,and even developing prevention and treatment strategies.
