Sepiolite(ST) was used as a supporting matrix in compiste phase change materials(PCMs) due to its unique microstructure, good thermal stability, and other raw material advantages. In this paper, microwave acid treatme...Sepiolite(ST) was used as a supporting matrix in compiste phase change materials(PCMs) due to its unique microstructure, good thermal stability, and other raw material advantages. In this paper, microwave acid treatment were innovatively used for the modification of sepiolite. The modified sepiolite(ST_(m)) obtained in different hydrochloric acid concentrations(0.25, 0.5, 0.75, and 1.0 mol·L^(-1)) was added to stearic acid(SA) via vacuum impregnation method. The thermophysical properties of the composites were changed by varying the hydrochloric acid concentration. The SA-ST_(m0.5)obtained by microwave acid treatment at 0.5 mol·L^(-1)hydrochloric acid concentration showed a higher loading capacity(82.63%) than other composites according to the differential scanning calorimeter(DSC) analysis. The melting and freezing enthalpies of SA-ST_(m0.5)were of 152.30 and 148.90 J·g^(-1), respectively. The thermal conductivity of SA-ST_(m0.5)was as high as 1.52 times that of pure SA. In addition, the crystal structure, surface morphology, and microporous structure of ST_(m)were studied, and the mechanism of SAST_(m0.5)performance enhancement was further revealed by Brunauere Emmett Teller(BET) analysis. Leakage experiment showed that SAST_(m0.5)had a good morphological stability. These results demostrate that SA-ST_(m0.5)has a potential application in thermal energy storage.展开更多
Objective:The aim of the study was to evaluate the efficacy and toxicity of high power focused-beam microwave hyperthermia with intrapleural injection of Shapeilin for patients with malignant hydrothorax.Methods:Fifty...Objective:The aim of the study was to evaluate the efficacy and toxicity of high power focused-beam microwave hyperthermia with intrapleural injection of Shapeilin for patients with malignant hydrothorax.Methods:Fifty-eight patients with malignant hydrothorax were divided into group A and group B randomly.All patients underwent indwelling pleural catheter and were treated by intrapleural injection of Shapeilin once three days.Treatment was composed of 3 times injection.Patients of group B received high power focused-beam microwave hyperthermia after injection of Shapeilin.Results:The response rate of group B(79.3%) was higher than that of group A(48.3%)(P < 0.05).Incidence of main adverse reactions,associated with Shapeilin,of two groups including fever and thoracodynia were similar(P > 0.05).Patients of group B didn't encounter severe toxicities of microwave hyperthermia.Conclusion:High power focused-beam microwave hyperthermia combined with intrapleural injection of Shapeilin is effective and tolerable for patients with malignant hydrothorax.展开更多
Objective: The aim of this study was to investigate the side effects of docetaxel with cyclophosphamide as postoperative adjuvant chemotherapy for elderly breast cancer patients. Methods: Thirty-six operable elderly b...Objective: The aim of this study was to investigate the side effects of docetaxel with cyclophosphamide as postoperative adjuvant chemotherapy for elderly breast cancer patients. Methods: Thirty-six operable elderly breast cancer patients at intermediate risk based on the St Gallen risk classification underwent modified radical mastectomy and then were given four cycles of TC regimen (docetaxel 75 mg/m2 i.v. on day 1; cyclophosphamide 600 mg/m2 i.v. on day 1; every 21 days ). Primary prophylaxis granulocyte colony stimulating factor (G-CSF) 200μg i.h. was administered on day 4-6. Results: The main side effect was neutropenia. Grade 3 neutropenia developed in 36.1% and G4 in 19.4%, respectively. Most of the other side effects were G1-2. Dose reduction occurred in 11.1% patients. The completion rate of chemotherapy was 100%. Conclu-sion: Docetaxel with cyclophosphamide as postoperative adjuvant chemotherapy regimen with G-CSF primary prophylaxis is tolerable for elderly patients in general good condition.展开更多
This study uses the WRF-Chem model combined with the empirical kinetic modeling method(EKMA curve)to study the compound pollution event in Beijing that happened in 13−23 May 2017.Sensitivity tests are conducted to ana...This study uses the WRF-Chem model combined with the empirical kinetic modeling method(EKMA curve)to study the compound pollution event in Beijing that happened in 13−23 May 2017.Sensitivity tests are conducted to analyze ozone sensitivity to its precursors,and to develop emission reduction measures.The results suggest that the model can accurately simulate the compound pollution process of photochemistry and haze.When VOCs and NOx were reduced by the same proportion,the effect of O_(3)reduction at peak time was more obvious,and the effect during daytime was more significant than at night.The degree of change in ozone was peak time>daytime average.When reducing or increasing the ratio of precursors by 25%at the same time,the effect of reducing 25%VOCs on the average ozone concentration reduction was most significant.The degree of change in ozone decreased with increasing altitude,the location of the ozone maximum change shifted westward,and its range narrowed.As the altitude increases,the VOCs-limited zone decreases,VOCs sensitivity decreases,NOx sensitivity increases.The controlled area changed from near-surface VOCs-limited to high-altitude NOx-limited.Upon examining the EKMA curve,we have found that suburban and urban are sensitive to VOCs.The sensitivity tests indicate that when VOCs in suburban are reduced about 60%,the O_(3)-1h concentration could reach the standard,and when VOCs of the urban decreased by about 50%,the O_(3)-1h concentration could reach the standard.Thus,these findings could provide references for the control of compound air pollution in Beijing.展开更多
As a surface functional material,super-hydrophobic coating has great application potential in wind turbine blade anti-icing,self-cleaning and drag reduction.In this study,ZnO and SiO2 multi-scale superhydrophobic coat...As a surface functional material,super-hydrophobic coating has great application potential in wind turbine blade anti-icing,self-cleaning and drag reduction.In this study,ZnO and SiO2 multi-scale superhydrophobic coatings with mechanical flexibility were prepared by embedding modified ZnO and SiO2 nanoparticles in PDMS.The prepared coating has a higher static water contact angle(CA is 153°)and a lower rolling angle(SA is 3.3°),showing excellent super-hydrophobicity.Because of its excellent superhydrophobic ability and micro-nano structure,the coating has good anti-icing ability.Under the conditions of−10C and 60%relative humidity,the coating can delay the freezing time by 1511S,which is 10.7 times slower than the normal freezing time.More importantly,due to the mechanical properties provided by SiO2 and the synergistic effect of micro-nano particles,the coating has excellent mechanical durability.After 10 wear tests,the contact angle of the coating is still as high as 141°and the rolling angle is 6.8°.This research provides a theoretical reference for the preparation of a mechanically stable coating with a simple preparation process,as well as a basic research on the anti-icing behavior of the coating.展开更多
The temperature of aluminum alloy work-pieces in the aging furnace directly affects the quality of aluminum alloy products. Since the temperature of aluminum alloy work-pieces cannot be measured directly, a temperatur...The temperature of aluminum alloy work-pieces in the aging furnace directly affects the quality of aluminum alloy products. Since the temperature of aluminum alloy work-pieces cannot be measured directly, a temperature prediction model based on improved case-based reasoning (CBR) method is established to realize the online measurement of the work-pieces temperature. More specifically, the model is constructed by an advanced case-based reasoning method in which a state transition algorithm (STA) is firstly used to optimize the weights of feature attributes. In other words, STA is utilized to find the suitable attribute weights of the CBR model that can improve the accuracy of the case retrieval process. Finally, the CBR model based on STA (STCBR) was applied to predict the temperature of aluminum alloy work-pieces in the aging furnace. The results of the experiments indicated that the developed model can realize high-accuracy prediction of work-pieces temperature and it has good application prospects in the industrial field.展开更多
To the Editor:In the last decade,neoadjuvant chemotherapy(NAC)has become a well-accepted treatment option for breast cancer,although few detailed description of NAC in China has yet been reported.[1]A previous study f...To the Editor:In the last decade,neoadjuvant chemotherapy(NAC)has become a well-accepted treatment option for breast cancer,although few detailed description of NAC in China has yet been reported.[1]A previous study found that among patients with clinically node-negative(cN0)breast cancer,97.7%(432/442)with breast pathologic complete response(bpCR)had ypN0(absence of metastases in the axillary lymph nodes);and 71.6%(882/1232)without bpCR achieved ypN0(P<0.001).As for human epidermal growth factor receptor 2(HER2)positive or triple-negative breast cancer(TNBC)that achieved bpCR.展开更多
The ^(25)Mg(p,γ)^(26)Al reaction plays an important role in the study of cosmic 1.809 MeV γ-ray as a signature of ongoing nucleosynthesis in the Galaxy.At astrophysical temperature around 0.1 GK,the ^(25)Mg(p,γ)^(2...The ^(25)Mg(p,γ)^(26)Al reaction plays an important role in the study of cosmic 1.809 MeV γ-ray as a signature of ongoing nucleosynthesis in the Galaxy.At astrophysical temperature around 0.1 GK,the ^(25)Mg(p,γ)^(26)Al reaction rates are dominated by the 92 keV resonance capture process.We report a precise measurement of the 92 keV ^(25)Mg(p,γ)^(26)Al resonance in the day-one experiment at Jinping Underground Nuclear Astrophysics experiment(JUNA)facility in the China Jinping Underground Laboratory(CJPL).The resonance strength and ground state feeding factor are determined to be 3.8±0.3×10^(-10) eV and 0:660:04,respectively.The results are in agreement with those reported in the previous direct underground measurement within uncertainty,but with significantly reduced uncertainties.Consequently,we recommend new ^(25)Mg(p,γ)^(26)Al reaction rates which are by a factor of 2.4 larger than those adopted in REACLIB database at the temperature around 0.1 GK.The new results indicate higher production rates of ^(26g)Al and the cosmic 1.809 MeV γ-ray.The implication of the new rates for the understanding of other astrophysical situations is also discussed.展开更多
With the increase of different sensors,applications and customers,the demand from data providers and users is for a new geospatial data service model,which supports low cost,high dexterity,and which would provide a co...With the increase of different sensors,applications and customers,the demand from data providers and users is for a new geospatial data service model,which supports low cost,high dexterity,and which would provide a comprehensive service.Based on such requirements and demands,the 21AT TripleSat constellation terminal and data delivery and management system has been developed by a Beijing based high-tech enterprise,Twenty First Century Aerospace Technology Co.,Ltd.(21AT).The company is the first commercial Earth observation satellite operator and service provider in China.This new geospatial data service model allows the user to directly access multi-source satellite data,manage the data order,and carry out automatic massive data production and delivery.The solution also implements safe and hierarchical user management,statistical data analysis,and automatic information reports.In addition,a mobile application is also available for users to easily access system functions.This new geospatial solution has already been successfully applied and installed in many customer sites in China,and is now available globally for international clients interested in fast geospatial solutions.It enables the success of customers’operational services.Besides providing TripleSat Constellation images,the multi-source data access system also allows the users to access other satellite data sources,based on customized agreement.This paper describes and discusses this new geospatial data service model.展开更多
To investigate the interannual variations of particulate matter (PM) pollution in winter, this paper examines the pollution characteristics of PM with aerodynamic diameters of less than 2.5 and 10 μm (i.e., PM2.5 ...To investigate the interannual variations of particulate matter (PM) pollution in winter, this paper examines the pollution characteristics of PM with aerodynamic diameters of less than 2.5 and 10 μm (i.e., PM2.5 and PM10), and their relationship to meteorological conditions over the Beijing municipality, Tianjin municipality, and Hebei Province--an area called Jing-Jin-Ji (JJJ, hereinafter)-in December 2013-16. The meteorological conditions during this period are also analyzed. The regional average concentrations of PM2.5 (PM10) over the JJJ area during this period were 148.6 (236.4), 100.1 (166.4), 140.5 (204.5), and 141.7 (203.1) μg m^-3, respectively. The high occurrence frequencies of cold air outbreaks, a strong Siberian high, high wind speeds and boundary layer height, and low temperature and relative humidity, were direct meteorological causes of the low PM concentration in December 2014. A combined analysis of PM pollution and meteorological conditions implied that control measures have resulted in an effective improvement in air quality. Using the same emissions inventory in December 2013-16, a modeling analysis showed emissions of PM2.5 to decrease by 12.7%, 8.6%, and 8.3% in December 2014, 2015, and 2016, respectively, each compared with the previous year, over the JJJ area.展开更多
During the 2012 Lanzhou International Marathon, the local government made a significant effort to improve traffic conditions and air quality by implementing traffic restriction measures. To evaluate the direct effect ...During the 2012 Lanzhou International Marathon, the local government made a significant effort to improve traffic conditions and air quality by implementing traffic restriction measures. To evaluate the direct effect of these measures on urban air quality, especially particle concentrations and their size distributions, atmospheric particle size distributions (0.5-20μm) obtained using an aerodynamic particle sizer (model 3321, TSI, USA) in June 2012 were analyzed. It was found that the particle number, surface area and volume concentrations for size range 0.5-10 μm were (15.0±2.1) cm-3, (11.8±2.6) μm2/cm3 and (1.9±0.6) μm2/cm3, respectively, on the traffic-restricted day (Sunday), which is 63.2%, 53.0% and 47.2% lower than those on a normal Sunday. For number and surface area concentrations, the most affected size range was 0.5-0.7 and 0.5-0.8 μm, respectively, while for volume concentration, the most affected size ranges were 0.5-0.8, 1.7-2.0 and 5.0-5.4 μm. Number and volume concentrations of particles in size range 0.5-1.0μm correlated well with the number of non-CNG (Compressed Natural Gas) powered vehicles, while their correlation with the number of CNG-powered vehicles was very low, suggesting that reasonable urban traffic controls along with vehicle technology improvements could play an important role in improving urban air quality.展开更多
The role of PM_(2.5)(particles with aerodynamic diameters≤_(2.5)μm)deposition in air quality changes over China remains unclear.By using the three-year(2013,2015,and 2017)simulation results of the WRF/CUACE v1.0 mod...The role of PM_(2.5)(particles with aerodynamic diameters≤_(2.5)μm)deposition in air quality changes over China remains unclear.By using the three-year(2013,2015,and 2017)simulation results of the WRF/CUACE v1.0 model from a previous work(Zhang et al.,2021),a non-linear relationship between the deposition of PM_(2.5)and anthropogenic emissions over central-eastern China in cold seasons as well as in different life stages of haze events was unraveled.PM_(2.5)deposition is spatially distributed differently from PM_(2.5)concentrations and anthropogenic emissions over China.The North China Plain(NCP)is typically characterized by higher anthropogenic emissions compared to southern China,such as the middlelow reaches of Yangtze River(MLYR),which includes parts of the Yangtze River Delta and the Midwest.However,PM_(2.5)deposition in the NCP is significantly lower than that in the MLYR region,suggesting that in addition to meteorology and emissions,lower deposition is another important factor in the increase in haze levels.Regional transport of pollution in central-eastern China acts as a moderator of pollution levels in different regions,for example by bringing pollution from the NCP to the MLYR region in cold seasons.It was found that in typical haze events the deposition flux of PM_(2.5)during the removal stages is substantially higher than that in accumulation stages,with most of the PM_(2.5)being transported southward and deposited to the MLYR and Sichuan Basin region,corresponding to a latitude range of about 24°N-31°N.展开更多
Exosomes secreted by tumor cells carry abundant molecular biomarkers that reflect the status of their originating cells.These tumor-derived exosomes(TDEs)have emerged as attractive diagnostic targets.However,the ident...Exosomes secreted by tumor cells carry abundant molecular biomarkers that reflect the status of their originating cells.These tumor-derived exosomes(TDEs)have emerged as attractive diagnostic targets.However,the identification and characterization of highly heterogeneous TDEs remain practically challenging.Here,we report a dual rolling circle amplification(DRCA)-assisted approach for the selective encapsulation of single TDEs for fluorescence microscopic and flow cytometric analysis.TDEs have been targeted by aptamers that recognized their surface tumor marker and exosomal marker CD63,following DRCA that produced entangling polymeric DNA chains,resulting in facile particle enlargement that allows single-particle fluorescence profiling of exosome heterogeneity.We have demonstrated the use of a dual-marker positive ratio for exosome differentiation and applied division and multiplication operations for normalized andmagnified marker heterogeneity analysis.We further applied this assay to distinguish lung adenocarcinoma and pulmonary nodule patients and found an accuracy of 90%.We anticipate promising transformations of this straightforward assay into clinically implantable diagnostic methods.展开更多
In 2014, the National Natural Science Foundation of China (NSFC) approved the Jinping Underground Nuclear Astrophysics laboratory (JUNA) project, which aims at direct cross-section measurements of four key stellar...In 2014, the National Natural Science Foundation of China (NSFC) approved the Jinping Underground Nuclear Astrophysics laboratory (JUNA) project, which aims at direct cross-section measurements of four key stellar nuclear reactions right down to the Gamow windows. In order to solve the observed fluorine overabundances in Asymptotic Giant Branch (AGB) stars, measuring the key 19F(p,a)16O reaction at effective burning energies (i.e., at Gamow window) is established as one of the scientific research sub-projects. The present paper describes this sub-project in details, including motivation, status, experimental setup, yield and background estimation, aboveground test, as well as other relevant reactions.展开更多
基金financially supported by the National Natural Science Foundation of China (No.52274252)the Special Fund for the Construction of Innovative Provinces in Hunan Province,China (Nos.2020RC3038 and 2022WK4004)the Changsha City Fund for Distinguished and Innovative Young Scholars,China (No.kq1802007)。
文摘Sepiolite(ST) was used as a supporting matrix in compiste phase change materials(PCMs) due to its unique microstructure, good thermal stability, and other raw material advantages. In this paper, microwave acid treatment were innovatively used for the modification of sepiolite. The modified sepiolite(ST_(m)) obtained in different hydrochloric acid concentrations(0.25, 0.5, 0.75, and 1.0 mol·L^(-1)) was added to stearic acid(SA) via vacuum impregnation method. The thermophysical properties of the composites were changed by varying the hydrochloric acid concentration. The SA-ST_(m0.5)obtained by microwave acid treatment at 0.5 mol·L^(-1)hydrochloric acid concentration showed a higher loading capacity(82.63%) than other composites according to the differential scanning calorimeter(DSC) analysis. The melting and freezing enthalpies of SA-ST_(m0.5)were of 152.30 and 148.90 J·g^(-1), respectively. The thermal conductivity of SA-ST_(m0.5)was as high as 1.52 times that of pure SA. In addition, the crystal structure, surface morphology, and microporous structure of ST_(m)were studied, and the mechanism of SAST_(m0.5)performance enhancement was further revealed by Brunauere Emmett Teller(BET) analysis. Leakage experiment showed that SAST_(m0.5)had a good morphological stability. These results demostrate that SA-ST_(m0.5)has a potential application in thermal energy storage.
文摘Objective:The aim of the study was to evaluate the efficacy and toxicity of high power focused-beam microwave hyperthermia with intrapleural injection of Shapeilin for patients with malignant hydrothorax.Methods:Fifty-eight patients with malignant hydrothorax were divided into group A and group B randomly.All patients underwent indwelling pleural catheter and were treated by intrapleural injection of Shapeilin once three days.Treatment was composed of 3 times injection.Patients of group B received high power focused-beam microwave hyperthermia after injection of Shapeilin.Results:The response rate of group B(79.3%) was higher than that of group A(48.3%)(P < 0.05).Incidence of main adverse reactions,associated with Shapeilin,of two groups including fever and thoracodynia were similar(P > 0.05).Patients of group B didn't encounter severe toxicities of microwave hyperthermia.Conclusion:High power focused-beam microwave hyperthermia combined with intrapleural injection of Shapeilin is effective and tolerable for patients with malignant hydrothorax.
文摘Objective: The aim of this study was to investigate the side effects of docetaxel with cyclophosphamide as postoperative adjuvant chemotherapy for elderly breast cancer patients. Methods: Thirty-six operable elderly breast cancer patients at intermediate risk based on the St Gallen risk classification underwent modified radical mastectomy and then were given four cycles of TC regimen (docetaxel 75 mg/m2 i.v. on day 1; cyclophosphamide 600 mg/m2 i.v. on day 1; every 21 days ). Primary prophylaxis granulocyte colony stimulating factor (G-CSF) 200μg i.h. was administered on day 4-6. Results: The main side effect was neutropenia. Grade 3 neutropenia developed in 36.1% and G4 in 19.4%, respectively. Most of the other side effects were G1-2. Dose reduction occurred in 11.1% patients. The completion rate of chemotherapy was 100%. Conclu-sion: Docetaxel with cyclophosphamide as postoperative adjuvant chemotherapy regimen with G-CSF primary prophylaxis is tolerable for elderly patients in general good condition.
基金This study is funded by Air Pollution Special Project of the Ministry of Science and Technology(Grant No.2017YFCOZ10006)the National Natural Science Foundation of China(Grant No.41975173)。
文摘This study uses the WRF-Chem model combined with the empirical kinetic modeling method(EKMA curve)to study the compound pollution event in Beijing that happened in 13−23 May 2017.Sensitivity tests are conducted to analyze ozone sensitivity to its precursors,and to develop emission reduction measures.The results suggest that the model can accurately simulate the compound pollution process of photochemistry and haze.When VOCs and NOx were reduced by the same proportion,the effect of O_(3)reduction at peak time was more obvious,and the effect during daytime was more significant than at night.The degree of change in ozone was peak time>daytime average.When reducing or increasing the ratio of precursors by 25%at the same time,the effect of reducing 25%VOCs on the average ozone concentration reduction was most significant.The degree of change in ozone decreased with increasing altitude,the location of the ozone maximum change shifted westward,and its range narrowed.As the altitude increases,the VOCs-limited zone decreases,VOCs sensitivity decreases,NOx sensitivity increases.The controlled area changed from near-surface VOCs-limited to high-altitude NOx-limited.Upon examining the EKMA curve,we have found that suburban and urban are sensitive to VOCs.The sensitivity tests indicate that when VOCs in suburban are reduced about 60%,the O_(3)-1h concentration could reach the standard,and when VOCs of the urban decreased by about 50%,the O_(3)-1h concentration could reach the standard.Thus,these findings could provide references for the control of compound air pollution in Beijing.
基金funded by the Changsha University of Science and Technology Research and Innovation Project(CX2019SS21)the National Energy Group Technology Innovation Project(HJLFD-QTHT-2019-09).
文摘As a surface functional material,super-hydrophobic coating has great application potential in wind turbine blade anti-icing,self-cleaning and drag reduction.In this study,ZnO and SiO2 multi-scale superhydrophobic coatings with mechanical flexibility were prepared by embedding modified ZnO and SiO2 nanoparticles in PDMS.The prepared coating has a higher static water contact angle(CA is 153°)and a lower rolling angle(SA is 3.3°),showing excellent super-hydrophobicity.Because of its excellent superhydrophobic ability and micro-nano structure,the coating has good anti-icing ability.Under the conditions of−10C and 60%relative humidity,the coating can delay the freezing time by 1511S,which is 10.7 times slower than the normal freezing time.More importantly,due to the mechanical properties provided by SiO2 and the synergistic effect of micro-nano particles,the coating has excellent mechanical durability.After 10 wear tests,the contact angle of the coating is still as high as 141°and the rolling angle is 6.8°.This research provides a theoretical reference for the preparation of a mechanically stable coating with a simple preparation process,as well as a basic research on the anti-icing behavior of the coating.
文摘The temperature of aluminum alloy work-pieces in the aging furnace directly affects the quality of aluminum alloy products. Since the temperature of aluminum alloy work-pieces cannot be measured directly, a temperature prediction model based on improved case-based reasoning (CBR) method is established to realize the online measurement of the work-pieces temperature. More specifically, the model is constructed by an advanced case-based reasoning method in which a state transition algorithm (STA) is firstly used to optimize the weights of feature attributes. In other words, STA is utilized to find the suitable attribute weights of the CBR model that can improve the accuracy of the case retrieval process. Finally, the CBR model based on STA (STCBR) was applied to predict the temperature of aluminum alloy work-pieces in the aging furnace. The results of the experiments indicated that the developed model can realize high-accuracy prediction of work-pieces temperature and it has good application prospects in the industrial field.
基金Beijing Medical Reward Foundation(No.YXJL-2016-0040-0012)
文摘To the Editor:In the last decade,neoadjuvant chemotherapy(NAC)has become a well-accepted treatment option for breast cancer,although few detailed description of NAC in China has yet been reported.[1]A previous study found that among patients with clinically node-negative(cN0)breast cancer,97.7%(432/442)with breast pathologic complete response(bpCR)had ypN0(absence of metastases in the axillary lymph nodes);and 71.6%(882/1232)without bpCR achieved ypN0(P<0.001).As for human epidermal growth factor receptor 2(HER2)positive or triple-negative breast cancer(TNBC)that achieved bpCR.
基金supported by the National Natural Science Foundation of China(1149056312125509U18672111196114100311775133and 12175152)the Continuous Basic Scientific Research Project No.WDJC-2019-13+1 种基金the Equipment Research and Development Project of Chinese Academy of Sciences(28Y531040)research fund of CNNC。
文摘The ^(25)Mg(p,γ)^(26)Al reaction plays an important role in the study of cosmic 1.809 MeV γ-ray as a signature of ongoing nucleosynthesis in the Galaxy.At astrophysical temperature around 0.1 GK,the ^(25)Mg(p,γ)^(26)Al reaction rates are dominated by the 92 keV resonance capture process.We report a precise measurement of the 92 keV ^(25)Mg(p,γ)^(26)Al resonance in the day-one experiment at Jinping Underground Nuclear Astrophysics experiment(JUNA)facility in the China Jinping Underground Laboratory(CJPL).The resonance strength and ground state feeding factor are determined to be 3.8±0.3×10^(-10) eV and 0:660:04,respectively.The results are in agreement with those reported in the previous direct underground measurement within uncertainty,but with significantly reduced uncertainties.Consequently,we recommend new ^(25)Mg(p,γ)^(26)Al reaction rates which are by a factor of 2.4 larger than those adopted in REACLIB database at the temperature around 0.1 GK.The new results indicate higher production rates of ^(26g)Al and the cosmic 1.809 MeV γ-ray.The implication of the new rates for the understanding of other astrophysical situations is also discussed.
基金supported by the project of Beijing Municipal Science and Technology Commission and Science and Technology Innovation Base of Cultivating and Developing Engineering[grant number Z161100005016069]the National High Technology Research and Development Program[grant number 2013AA12A303].
文摘With the increase of different sensors,applications and customers,the demand from data providers and users is for a new geospatial data service model,which supports low cost,high dexterity,and which would provide a comprehensive service.Based on such requirements and demands,the 21AT TripleSat constellation terminal and data delivery and management system has been developed by a Beijing based high-tech enterprise,Twenty First Century Aerospace Technology Co.,Ltd.(21AT).The company is the first commercial Earth observation satellite operator and service provider in China.This new geospatial data service model allows the user to directly access multi-source satellite data,manage the data order,and carry out automatic massive data production and delivery.The solution also implements safe and hierarchical user management,statistical data analysis,and automatic information reports.In addition,a mobile application is also available for users to easily access system functions.This new geospatial solution has already been successfully applied and installed in many customer sites in China,and is now available globally for international clients interested in fast geospatial solutions.It enables the success of customers’operational services.Besides providing TripleSat Constellation images,the multi-source data access system also allows the users to access other satellite data sources,based on customized agreement.This paper describes and discusses this new geospatial data service model.
基金Supported by the National Natural Science Foundation of China(91544232 and 51305112)Chinese Academy of Meteorological Sciences Basic Research Project(2017Y001)National Science and Technology Support Program of China(2014BAC16B03 and2014BAC23B01)
文摘To investigate the interannual variations of particulate matter (PM) pollution in winter, this paper examines the pollution characteristics of PM with aerodynamic diameters of less than 2.5 and 10 μm (i.e., PM2.5 and PM10), and their relationship to meteorological conditions over the Beijing municipality, Tianjin municipality, and Hebei Province--an area called Jing-Jin-Ji (JJJ, hereinafter)-in December 2013-16. The meteorological conditions during this period are also analyzed. The regional average concentrations of PM2.5 (PM10) over the JJJ area during this period were 148.6 (236.4), 100.1 (166.4), 140.5 (204.5), and 141.7 (203.1) μg m^-3, respectively. The high occurrence frequencies of cold air outbreaks, a strong Siberian high, high wind speeds and boundary layer height, and low temperature and relative humidity, were direct meteorological causes of the low PM concentration in December 2014. A combined analysis of PM pollution and meteorological conditions implied that control measures have resulted in an effective improvement in air quality. Using the same emissions inventory in December 2013-16, a modeling analysis showed emissions of PM2.5 to decrease by 12.7%, 8.6%, and 8.3% in December 2014, 2015, and 2016, respectively, each compared with the previous year, over the JJJ area.
基金supported by the Hundred Talents Program of Chinese Academy of Sciences (No. 29O827631)
文摘During the 2012 Lanzhou International Marathon, the local government made a significant effort to improve traffic conditions and air quality by implementing traffic restriction measures. To evaluate the direct effect of these measures on urban air quality, especially particle concentrations and their size distributions, atmospheric particle size distributions (0.5-20μm) obtained using an aerodynamic particle sizer (model 3321, TSI, USA) in June 2012 were analyzed. It was found that the particle number, surface area and volume concentrations for size range 0.5-10 μm were (15.0±2.1) cm-3, (11.8±2.6) μm2/cm3 and (1.9±0.6) μm2/cm3, respectively, on the traffic-restricted day (Sunday), which is 63.2%, 53.0% and 47.2% lower than those on a normal Sunday. For number and surface area concentrations, the most affected size range was 0.5-0.7 and 0.5-0.8 μm, respectively, while for volume concentration, the most affected size ranges were 0.5-0.8, 1.7-2.0 and 5.0-5.4 μm. Number and volume concentrations of particles in size range 0.5-1.0μm correlated well with the number of non-CNG (Compressed Natural Gas) powered vehicles, while their correlation with the number of CNG-powered vehicles was very low, suggesting that reasonable urban traffic controls along with vehicle technology improvements could play an important role in improving urban air quality.
基金supported by the National Key Foundation Study Developing Programs(Nos.2019YFC0214801 and 2019YFC0214601)the National Natural Science Foundation of China(Nos.42090030,41975131 and 91744209)the CAMS Basic Research Project(No.2020Y001)。
文摘The role of PM_(2.5)(particles with aerodynamic diameters≤_(2.5)μm)deposition in air quality changes over China remains unclear.By using the three-year(2013,2015,and 2017)simulation results of the WRF/CUACE v1.0 model from a previous work(Zhang et al.,2021),a non-linear relationship between the deposition of PM_(2.5)and anthropogenic emissions over central-eastern China in cold seasons as well as in different life stages of haze events was unraveled.PM_(2.5)deposition is spatially distributed differently from PM_(2.5)concentrations and anthropogenic emissions over China.The North China Plain(NCP)is typically characterized by higher anthropogenic emissions compared to southern China,such as the middlelow reaches of Yangtze River(MLYR),which includes parts of the Yangtze River Delta and the Midwest.However,PM_(2.5)deposition in the NCP is significantly lower than that in the MLYR region,suggesting that in addition to meteorology and emissions,lower deposition is another important factor in the increase in haze levels.Regional transport of pollution in central-eastern China acts as a moderator of pollution levels in different regions,for example by bringing pollution from the NCP to the MLYR region in cold seasons.It was found that in typical haze events the deposition flux of PM_(2.5)during the removal stages is substantially higher than that in accumulation stages,with most of the PM_(2.5)being transported southward and deposited to the MLYR and Sichuan Basin region,corresponding to a latitude range of about 24°N-31°N.
基金supported by the National Key Research Program(grant no.2019YFA0905800)the NSFC Program(grant no.22090053)the Natural Science Foundation of Hunan Province(grant no.2021JJ40040).
文摘Exosomes secreted by tumor cells carry abundant molecular biomarkers that reflect the status of their originating cells.These tumor-derived exosomes(TDEs)have emerged as attractive diagnostic targets.However,the identification and characterization of highly heterogeneous TDEs remain practically challenging.Here,we report a dual rolling circle amplification(DRCA)-assisted approach for the selective encapsulation of single TDEs for fluorescence microscopic and flow cytometric analysis.TDEs have been targeted by aptamers that recognized their surface tumor marker and exosomal marker CD63,following DRCA that produced entangling polymeric DNA chains,resulting in facile particle enlargement that allows single-particle fluorescence profiling of exosome heterogeneity.We have demonstrated the use of a dual-marker positive ratio for exosome differentiation and applied division and multiplication operations for normalized andmagnified marker heterogeneity analysis.We further applied this assay to distinguish lung adenocarcinoma and pulmonary nodule patients and found an accuracy of 90%.We anticipate promising transformations of this straightforward assay into clinically implantable diagnostic methods.
基金supported by the National Natural Science Foundation of China(Grant Nos.114905621149056011135005 and 11321064)
文摘In 2014, the National Natural Science Foundation of China (NSFC) approved the Jinping Underground Nuclear Astrophysics laboratory (JUNA) project, which aims at direct cross-section measurements of four key stellar nuclear reactions right down to the Gamow windows. In order to solve the observed fluorine overabundances in Asymptotic Giant Branch (AGB) stars, measuring the key 19F(p,a)16O reaction at effective burning energies (i.e., at Gamow window) is established as one of the scientific research sub-projects. The present paper describes this sub-project in details, including motivation, status, experimental setup, yield and background estimation, aboveground test, as well as other relevant reactions.