Alloying with Gd and Ag can significantly enhance the comprehensive properties of magnesium alloys,and accurate phase equilibria are a necessity for advanced alloy design.However,literature review reveals limited info...Alloying with Gd and Ag can significantly enhance the comprehensive properties of magnesium alloys,and accurate phase equilibria are a necessity for advanced alloy design.However,literature review reveals limited information on the phase equilibria in the ternary Mg-Gd-Ag system.Thus,in this paper,the phase equilibria of the ternary Mg-Gd-Ag system in the region of 0-50 at.%Gd at 450℃and 500℃were investigated by combining the electron probe microanalysis and X-ray diffraction of totally 66 equilibrated alloys,with two isothermal sections at 450℃and 500℃established accordingly;and relatively high solid solubility of Ag in GdMg_(3)was characterized.Moreover,seven ternary compounds(denoted asτ_(1)toτ_(7))were found,and their crystal structures were refined by using Rietveld method.Theτ_(1)was identical to the previously reported X phase with a diamond-cubic structure,while the remaining six ternary compounds(τ_(2)toτ_(7))were newly found.The seven ternary compounds(τ_(1)toτ_(7))are among the space groups of Fd3m(τ_(1)),P4/nmm(τ_(2)),P63mc(τ_(3)),P63mc(τ_(4)),Pmn2_(1)(τ_(5)),P62m(τ_(6))and Pc(τ_(7)).Their homogeneity ranges and lattice parameters were carefully determined.The solubilities of the third elements in the binary compounds of the three subsystems were also well measured.It is anticipated that the presently obtained phase equilibria as well as the crystal structures of ternary compounds in the Mg-Gd-Ag system would serve as a foundation for developing thermodynamic database and alloy design in the near future.展开更多
PM_(2.5) and black carbon(BC)are important air pollutants impacting radiation balance,air quality,health,and ecosystems.Ozone(O_(3))levels are increasing despite decreases in other pollutants,posing a challenge for po...PM_(2.5) and black carbon(BC)are important air pollutants impacting radiation balance,air quality,health,and ecosystems.Ozone(O_(3))levels are increasing despite decreases in other pollutants,posing a challenge for pollution control,especially in coastal cities like Zhoushan,where the monsoonal climate can exacerbate PM_(2.5) and ozone pollution.This study conducted continuous online measurements of major atmospheric pollutants in Zhoushan,Zhejiang Province,in 2020.The results indicate that the highest contribution from local air masses in Zhoushan is observed in spring,accounting for 17.7%,while the greatest average contribution from northern Zhejiang Province,Jiangsu Province,and Shanghai occurs in winter,at 18.5%.Pollutant concentrationswere seasonally variable,with PM_(2.5),BC,and sulfur dioxide concentrations 56.6%,36%,and 58.2%higher in the cold season compared to the warm season.The O_(3) in spring is approximately 50%higher than that in summer.Ship emissions significantly contributed to BC,nitrogen oxides(NO_(x)),and carbon monoxide in Zhoushan.In spring,PM_(2.5) sources included photochemical processes and northern air mass transport,while in winter,PM_(2.5) was due to regional transport.The inhibitory effect of PM_(2.5) on O_(3) formation in the Zhoushan area is relatively weak.Reducing NO_(x) emissions may increase O_(3),emphasizing the need for volatile organic compounds monitoring and regional control measures to improve air quality and ensure sustainable development in Zhoushan.展开更多
A field campaign was conducted to study the PM2.5 and atmospheric gases and aerosol’s components to evaluate the efficacy of radical measures implemented by the Chinese government to improve air quality during the 20...A field campaign was conducted to study the PM2.5 and atmospheric gases and aerosol’s components to evaluate the efficacy of radical measures implemented by the Chinese government to improve air quality during the 2016 G20 Summit in Hangzhou China.The lower level of PM2.5(32.48±11.03μg/m3)observed during the control period compared to precontrol and post-control periods showed that PM2.5 was alleviated by control policies.Based on the mass concentrations of particulate components,the emissions of PM2.5 from local sources including fossil fuel,coal combustion,industry and construction were effectively reduced,but non-exhaust emission was not reduced as effectively as expected.The accumulation of SNA(SO42-,NO3-,NH4+)was observed during the control period,due to the favourable synoptic weather conditions for photochemical reactions and heterogeneous hydrolysis.Because of transboundary transport during the control period,air masses from remote areas contributed significantly to local PM2.5.Although,secondary organic carbon(OCsec)exhibited more sensitivity than primary organic carbon(OCpri)to control measures,and the increased nitrogen oxidation ratio(NOR)implied the regional transport of aged sec-ondary aerosols to the study area.Overall,the results from various approaches revealed that local pollution sources were kept under control,indicating that the implementation of mitigation measures were helpful in improving the air quality of Hangzhou during G20 summit.To reduce ambient levels of PM2.5 further in Hangzhou,regional control policies may have to be taken so as to reduce the impact of long-range transport of air masses from inland China.展开更多
Hydrofluorocarbons(HFCs)have been widely used in China as substitutes for ozone-depleting substances,the production and use of which are being phased out under the Montreal Protocol.China is a major consumer of HFCs a...Hydrofluorocarbons(HFCs)have been widely used in China as substitutes for ozone-depleting substances,the production and use of which are being phased out under the Montreal Protocol.China is a major consumer of HFCs around the world,with its HFC emissions in CO2-equivalent contributing to about 18%of the global emissions for the period2012-16.Three methods are widely used to estimate the emissions of HFCs-namely,the bottom-up method,top-down method and tracer ratio method.In this study,the tracer ratio method was adopted to estimate HFC emissions in the Yangtze River Delta(YRD),using CO as a tracer.The YRD region might make a significant contribution to Chinese totals owing to its rapid economic growth.Weekly flask measurements for ten HFCs(HFC-23,HFC-32,HFC-125,HFC-134 a,HFC-143 a,HFC-152 a,HFC-227 ea,HFC-236 fa,HFC-245 fa and HFC-365 mfc)were conducted at Lin’an Regional Background Station in the YRD over the period 2012-16,and the HFC emissions were 2.4±1.4 Gg yr-1 for HFC-23,2.8±1.2 Gg yr-1 for HFC-32,2.2±1.2 Gg yr-1 for HFC-125,4.8±4.8 Gg yr-1 for HFC-134 a,0.9±0.6 Gg yr-1 for HFC-152 a,0.3±0.3 Gg yr-1 for HFC-227 ea and 0.3±0.2 Gg yr-1 for HFC-245 fa.The YRD total HFC emissions reached 53 Gg CO2-e yr-1,contributing 34%of the national total.The per capita HFC CO2-equivalent emissions rate was 240 kg yr-1,while the values of per unit area emissions and per million GDP emissions reached 150 Mg km-2yr-1 and 3500 kg yr-1(million CNY GDP)-1,which were much higher than national or global levels.展开更多
In the original version of this article,the unit of the YRD total HFC emissions“Gg CO2-e yr^−1”in the abstract should be Tg CO2-e yr^−1.On Page 581,in the fifth line from the left bottom,the unit of the total CO2-eq...In the original version of this article,the unit of the YRD total HFC emissions“Gg CO2-e yr^−1”in the abstract should be Tg CO2-e yr^−1.On Page 581,in the fifth line from the left bottom,the unit of the total CO2-equivalent emissions of HFCs“Gg yr^−1”should be Tg yr^−1.展开更多
Low-rank tensor completion(LRTC)restores missing elements in multidimensional visual data;the challenge is representing the inherent structures within this data.Typical methods either suffer from inefficiency owing to...Low-rank tensor completion(LRTC)restores missing elements in multidimensional visual data;the challenge is representing the inherent structures within this data.Typical methods either suffer from inefficiency owing to the combination of multiple regularizers or perform suboptimally using inappropriate priors.In this study,we further investigated LRTC using tensor singular value decomposition(t-SVD).Inspired by the tensor-tensor product(t-product),we proposed a unified transformed t-SVD method that employs an invertible linear transform with a unitary transform matrix.However,the t-SVD-based framework lacks the flexibility necessary to represent different inherent relations along the tensor modes.To address this issue,we propose a tensor represented by a series of multidimensional unfolding tensors to fully explore the hidden structure of the original data.Furthermore,the proposed model can be solved efficiently using the alternate-direction method of the multiplier(ADMM)approach.Extensive experimental results on multidimensional visual data(multispectral images,hyperspectral images,and videos)demonstrated the superiority of the proposed method over other state-of-the-art LRTC-related methods.展开更多
The spatial variability in the atmospheric CO_(2)and CH_(4)concentrations in urban land is affected by the source type,source distribution,and emission intensity in the cityscape.In this study,we analyzed vehicle-moun...The spatial variability in the atmospheric CO_(2)and CH_(4)concentrations in urban land is affected by the source type,source distribution,and emission intensity in the cityscape.In this study,we analyzed vehicle-mounted measurements of street-level CO_(2)and CH_(4)concentrations in Hangzhou—a large metropolitan area in the Yangtze River Delta in eastern China.The results revealed that CO_(2)and CH_(4)emission hotspots did not overlap geographically,with the former occurring as linear features at elevated road intersections and expressways and the latter occurring at waste treatment facilities(sewage treatment plants and landfills).The CH_(4):CO_(2)emission ratios(ppb ppm^(-1))were ranked in increasing order as follows:traffic(1.01±1.82;mean±1 SD);overall(3.46±2.71);sewage treatment(12.76±2.50);and landfill(36.50±10.15).Waste treatment was largely responsible for the increased overall emission ratio,supporting this source category as a major contributor to the CH_(4)budget in this city and suggesting a negligible role of domestic appliances(cookstoves and water heaters).A two-source mixing model calculation indicated that 99.9%of nonelectric vehicles in Hangzhou were gasoline-powered,revealing a recent shift in vehicle fuel composition from gasoline/natural gas to gasoline/electricity.The methodology established in this study is applicable to cities elsewhere.展开更多
Deep learning based techniques are broadly used in various applications, which exhibit superior performance compared to traditional methods. One of the mainstream topics in computer vision is the image super-resolutio...Deep learning based techniques are broadly used in various applications, which exhibit superior performance compared to traditional methods. One of the mainstream topics in computer vision is the image super-resolution task. In recent deep learning neural networks, the number of parameters in each convolution layer has increased along with more layers and feature maps, resulting in better image super-resolution performance. In today’s era, numerous service providers offer super-resolution services to users, providing them with remarkable convenience. However, the availability of open-source super-resolution services exposes service providers to the risk of copyright infringement, as the complete model could be vulnerable to leakage. Therefore, safeguarding the copyright of the complete model is a non-trivial concern. To tackle this issue, this paper presents a lightweight model as a substitute for the original complete model in image super-resolution. This research has identified smaller networks that can deliver impressive performance, while protecting the original model’s copyright. Finally, comprehensive experiments are conducted on multiple datasets to demonstrate the superiority of the proposed approach in generating super-resolution images even using lightweight neural networks.展开更多
基金support from the Natural Science Foundation of Hunan Province for Distinguished Young Scholars(No.2021JJ10062)is acknowledged.
文摘Alloying with Gd and Ag can significantly enhance the comprehensive properties of magnesium alloys,and accurate phase equilibria are a necessity for advanced alloy design.However,literature review reveals limited information on the phase equilibria in the ternary Mg-Gd-Ag system.Thus,in this paper,the phase equilibria of the ternary Mg-Gd-Ag system in the region of 0-50 at.%Gd at 450℃and 500℃were investigated by combining the electron probe microanalysis and X-ray diffraction of totally 66 equilibrated alloys,with two isothermal sections at 450℃and 500℃established accordingly;and relatively high solid solubility of Ag in GdMg_(3)was characterized.Moreover,seven ternary compounds(denoted asτ_(1)toτ_(7))were found,and their crystal structures were refined by using Rietveld method.Theτ_(1)was identical to the previously reported X phase with a diamond-cubic structure,while the remaining six ternary compounds(τ_(2)toτ_(7))were newly found.The seven ternary compounds(τ_(1)toτ_(7))are among the space groups of Fd3m(τ_(1)),P4/nmm(τ_(2)),P63mc(τ_(3)),P63mc(τ_(4)),Pmn2_(1)(τ_(5)),P62m(τ_(6))and Pc(τ_(7)).Their homogeneity ranges and lattice parameters were carefully determined.The solubilities of the third elements in the binary compounds of the three subsystems were also well measured.It is anticipated that the presently obtained phase equilibria as well as the crystal structures of ternary compounds in the Mg-Gd-Ag system would serve as a foundation for developing thermodynamic database and alloy design in the near future.
基金supported by Zhejiang Province Science Fund for Distinguished Young Scholars(No.LR24D050001)the Joint Funds of Zhejiang Provincial Natural Science Foundation of China(No.LZJMZ23D050002)+3 种基金the National Natural Science Foundation of China(No.42175116)the Scientific Research Foundation for Guilin University of Technology(No.GUTQDJJ2023046)supported by Guangxi Engineering Research Center of Comprehensive Treatment for Agricultural Non-Point Source Pollutionthe Modern Industry College of Ecology and Environmental Protection,Guilin University of Technology.
文摘PM_(2.5) and black carbon(BC)are important air pollutants impacting radiation balance,air quality,health,and ecosystems.Ozone(O_(3))levels are increasing despite decreases in other pollutants,posing a challenge for pollution control,especially in coastal cities like Zhoushan,where the monsoonal climate can exacerbate PM_(2.5) and ozone pollution.This study conducted continuous online measurements of major atmospheric pollutants in Zhoushan,Zhejiang Province,in 2020.The results indicate that the highest contribution from local air masses in Zhoushan is observed in spring,accounting for 17.7%,while the greatest average contribution from northern Zhejiang Province,Jiangsu Province,and Shanghai occurs in winter,at 18.5%.Pollutant concentrationswere seasonally variable,with PM_(2.5),BC,and sulfur dioxide concentrations 56.6%,36%,and 58.2%higher in the cold season compared to the warm season.The O_(3) in spring is approximately 50%higher than that in summer.Ship emissions significantly contributed to BC,nitrogen oxides(NO_(x)),and carbon monoxide in Zhoushan.In spring,PM_(2.5) sources included photochemical processes and northern air mass transport,while in winter,PM_(2.5) was due to regional transport.The inhibitory effect of PM_(2.5) on O_(3) formation in the Zhoushan area is relatively weak.Reducing NO_(x) emissions may increase O_(3),emphasizing the need for volatile organic compounds monitoring and regional control measures to improve air quality and ensure sustainable development in Zhoushan.
基金supported by the Ningbo Innovation Team Project(No.2017C510001)the Ningbo Municipal Bureau of Science and Technology Key Program(Nos.2019C10033,2019C10104)+4 种基金the National Natural Science Foundation of China(No.41975831)the Start-up Research Funding of South-Central University for Nationalities(No.YZZ18018)the Natural Science Foundation of Zhejiang Province(No.LY19D050002)the Provincial Key Laboratory Programme by Zhejiang Provincial Department of Science and Technology(No.2020E10018)。
文摘A field campaign was conducted to study the PM2.5 and atmospheric gases and aerosol’s components to evaluate the efficacy of radical measures implemented by the Chinese government to improve air quality during the 2016 G20 Summit in Hangzhou China.The lower level of PM2.5(32.48±11.03μg/m3)observed during the control period compared to precontrol and post-control periods showed that PM2.5 was alleviated by control policies.Based on the mass concentrations of particulate components,the emissions of PM2.5 from local sources including fossil fuel,coal combustion,industry and construction were effectively reduced,but non-exhaust emission was not reduced as effectively as expected.The accumulation of SNA(SO42-,NO3-,NH4+)was observed during the control period,due to the favourable synoptic weather conditions for photochemical reactions and heterogeneous hydrolysis.Because of transboundary transport during the control period,air masses from remote areas contributed significantly to local PM2.5.Although,secondary organic carbon(OCsec)exhibited more sensitivity than primary organic carbon(OCpri)to control measures,and the increased nitrogen oxidation ratio(NOR)implied the regional transport of aged sec-ondary aerosols to the study area.Overall,the results from various approaches revealed that local pollution sources were kept under control,indicating that the implementation of mitigation measures were helpful in improving the air quality of Hangzhou during G20 summit.To reduce ambient levels of PM2.5 further in Hangzhou,regional control policies may have to be taken so as to reduce the impact of long-range transport of air masses from inland China.
基金supported by the National Natural Science Foundation of China(Grant Nos.41575114 and 41730103)the Zhejiang Provincial Natural Science Foundation(Grant No.LY19D050002)the Meteorological Science and Technology Program of Zhejiang Province(Grant No.2019ZD12)。
文摘Hydrofluorocarbons(HFCs)have been widely used in China as substitutes for ozone-depleting substances,the production and use of which are being phased out under the Montreal Protocol.China is a major consumer of HFCs around the world,with its HFC emissions in CO2-equivalent contributing to about 18%of the global emissions for the period2012-16.Three methods are widely used to estimate the emissions of HFCs-namely,the bottom-up method,top-down method and tracer ratio method.In this study,the tracer ratio method was adopted to estimate HFC emissions in the Yangtze River Delta(YRD),using CO as a tracer.The YRD region might make a significant contribution to Chinese totals owing to its rapid economic growth.Weekly flask measurements for ten HFCs(HFC-23,HFC-32,HFC-125,HFC-134 a,HFC-143 a,HFC-152 a,HFC-227 ea,HFC-236 fa,HFC-245 fa and HFC-365 mfc)were conducted at Lin’an Regional Background Station in the YRD over the period 2012-16,and the HFC emissions were 2.4±1.4 Gg yr-1 for HFC-23,2.8±1.2 Gg yr-1 for HFC-32,2.2±1.2 Gg yr-1 for HFC-125,4.8±4.8 Gg yr-1 for HFC-134 a,0.9±0.6 Gg yr-1 for HFC-152 a,0.3±0.3 Gg yr-1 for HFC-227 ea and 0.3±0.2 Gg yr-1 for HFC-245 fa.The YRD total HFC emissions reached 53 Gg CO2-e yr-1,contributing 34%of the national total.The per capita HFC CO2-equivalent emissions rate was 240 kg yr-1,while the values of per unit area emissions and per million GDP emissions reached 150 Mg km-2yr-1 and 3500 kg yr-1(million CNY GDP)-1,which were much higher than national or global levels.
文摘In the original version of this article,the unit of the YRD total HFC emissions“Gg CO2-e yr^−1”in the abstract should be Tg CO2-e yr^−1.On Page 581,in the fifth line from the left bottom,the unit of the total CO2-equivalent emissions of HFCs“Gg yr^−1”should be Tg yr^−1.
基金supported by the Zhejiang Lab Key Research Project(No.G2021NB0AL03)Zhejiang Lab Youth Foundation Project(No.K2023NB0AA03).
文摘Low-rank tensor completion(LRTC)restores missing elements in multidimensional visual data;the challenge is representing the inherent structures within this data.Typical methods either suffer from inefficiency owing to the combination of multiple regularizers or perform suboptimally using inappropriate priors.In this study,we further investigated LRTC using tensor singular value decomposition(t-SVD).Inspired by the tensor-tensor product(t-product),we proposed a unified transformed t-SVD method that employs an invertible linear transform with a unitary transform matrix.However,the t-SVD-based framework lacks the flexibility necessary to represent different inherent relations along the tensor modes.To address this issue,we propose a tensor represented by a series of multidimensional unfolding tensors to fully explore the hidden structure of the original data.Furthermore,the proposed model can be solved efficiently using the alternate-direction method of the multiplier(ADMM)approach.Extensive experimental results on multidimensional visual data(multispectral images,hyperspectral images,and videos)demonstrated the superiority of the proposed method over other state-of-the-art LRTC-related methods.
基金supported by the National Natural Science Foundation of China(Grant Nos.U24A20590,42021004)the Joint funds of the Zhejiang Provincial Natural Science Foundation of China(GrantNo.LZJMZ23D050002)+2 种基金the 333 Project of Jiangsu Province(Grant No.BRA2022023)the Natural Science Foundation of Jiangsu Province for Distinguished Young Scholars(Grant No.BK20220055)the Key Laboratory of Ecosystem Carbon Source and Sink,China Meteorological Administration(Grant No.ECSS-CMA202302)。
文摘The spatial variability in the atmospheric CO_(2)and CH_(4)concentrations in urban land is affected by the source type,source distribution,and emission intensity in the cityscape.In this study,we analyzed vehicle-mounted measurements of street-level CO_(2)and CH_(4)concentrations in Hangzhou—a large metropolitan area in the Yangtze River Delta in eastern China.The results revealed that CO_(2)and CH_(4)emission hotspots did not overlap geographically,with the former occurring as linear features at elevated road intersections and expressways and the latter occurring at waste treatment facilities(sewage treatment plants and landfills).The CH_(4):CO_(2)emission ratios(ppb ppm^(-1))were ranked in increasing order as follows:traffic(1.01±1.82;mean±1 SD);overall(3.46±2.71);sewage treatment(12.76±2.50);and landfill(36.50±10.15).Waste treatment was largely responsible for the increased overall emission ratio,supporting this source category as a major contributor to the CH_(4)budget in this city and suggesting a negligible role of domestic appliances(cookstoves and water heaters).A two-source mixing model calculation indicated that 99.9%of nonelectric vehicles in Hangzhou were gasoline-powered,revealing a recent shift in vehicle fuel composition from gasoline/natural gas to gasoline/electricity.The methodology established in this study is applicable to cities elsewhere.
基金supported by the SW Copyright Ecosystem R&D Program through the Korea Creative Content Agency grant funded by the Ministry of Culture,Sports,and Tourism in 2023.Project Name:Development of Large-Scale Software License Verification Technology by Cloud Service Utilization and Construction Type(No.RS-2023-00224818).
文摘Deep learning based techniques are broadly used in various applications, which exhibit superior performance compared to traditional methods. One of the mainstream topics in computer vision is the image super-resolution task. In recent deep learning neural networks, the number of parameters in each convolution layer has increased along with more layers and feature maps, resulting in better image super-resolution performance. In today’s era, numerous service providers offer super-resolution services to users, providing them with remarkable convenience. However, the availability of open-source super-resolution services exposes service providers to the risk of copyright infringement, as the complete model could be vulnerable to leakage. Therefore, safeguarding the copyright of the complete model is a non-trivial concern. To tackle this issue, this paper presents a lightweight model as a substitute for the original complete model in image super-resolution. This research has identified smaller networks that can deliver impressive performance, while protecting the original model’s copyright. Finally, comprehensive experiments are conducted on multiple datasets to demonstrate the superiority of the proposed approach in generating super-resolution images even using lightweight neural networks.
