The radiation damage of three individual subcells for GalnP/GaAs//Ge triple-junction solar cells irradiated with electrons and protons is investigated using photoluminescence (PL) measurements. The PL spectra of each ...The radiation damage of three individual subcells for GalnP/GaAs//Ge triple-junction solar cells irradiated with electrons and protons is investigated using photoluminescence (PL) measurements. The PL spectra of each subcell are obtained using different excitation lasers. The PL intensity has a fast degradation after irradiation, and decreases as the displacement damage dose increases. Furthermore, the normalized PL intensity varying with the displacement damage dose is analyzed in detail, and then the lifetime damage coefficients of the recombination centers for GaInP top-cell, GaAs mid-cell and Ge bottom-cell of the triple-junction solar cells are determined from the PL radiative efficiency.展开更多
Multiple BAC-FISH is a powerful tool for modern cytogenetic researching in both animals and plants.But in cotton,this technique is unavailable due to the high percentage of repetitive sequences.
This work mainly focuses on the mineralogical study of particulate matter（PM10） in Beijing. Samples were collected on polycarbonate filter from April, 2002 to March, 2003 in Beijing urban area. Scanning electronic m...This work mainly focuses on the mineralogical study of particulate matter（PM10） in Beijing. Samples were collected on polycarbonate filter from April, 2002 to March, 2003 in Beijing urban area. Scanning electronic microscopy coupled with energy dispersive X-ray（SEM/EDX） was used to investigate individual mineral particles in Beijing PM10. 1454 individual mineral particulates from 48 samples were analysed by SEM/EDX. The results revealed that mineral particulates were complex and heterogeneous. 38 kinds of minerals in PM10 were identified. The clay minerals, of annual average percentage of 30.1%, were the main composition among the identified minerals, and illite/smectite was the main composition in clay minerals, reaching up to 35%. Annual average percentage of quartz, calcite, compound particulates, carbonates were 13.5%, 10.9%, 11.95%, 10.31%, respectively. Annual average percentage less than 10% were gypsum, feldspar, dolomite, and so on. Fluorite, apatite, halite, barite and chloridize zinc（ZnCl2） were firstly identified in Beijing PM10. Sulfurization was found on surface of mineral particles, suggested extensive atmospheric reaction in air during summer.展开更多
We analyze the radio spectral index of blazars from the University of Michigan Radio Astronomy Observatory database,and find that there exists quasiperiodic activity in 2251＋158.The long-term periodicity analysis is ...We analyze the radio spectral index of blazars from the University of Michigan Radio Astronomy Observatory database,and find that there exists quasiperiodic activity in 2251＋158.The long-term periodicity analysis is accomplished by three methods,which are the Jurkevich method（Jurkevich）,the discrete correlation function（DCF）,and the Periodogram method（P）.The results show that 2251＋158 has two strong periodicities,which are P1=6.3±1.1 yr and P2=3.8±1.2 yr.展开更多
An intense Asian dust storm invadedQinhuangdao,a coastal city ofNorth China on April 11-14,2023.We analyzed the bulk water-soluble inorganic ions(WSII)of PM_(10)and PM_(2.5)using an Ion Chromatograph and investigated ...An intense Asian dust storm invadedQinhuangdao,a coastal city ofNorth China on April 11-14,2023.We analyzed the bulk water-soluble inorganic ions(WSII)of PM_(10)and PM_(2.5)using an Ion Chromatograph and investigated individual particlemorphology and elemental composition using a scanning electron microscope coupled with energy dispersive X-ray.The results showed when the dust was directly transported to the sampling site from northwestern China(direct transport stages),the PM_(10)mass concentrations were high(675.0μg/m^(3))but the relative humidity(RH)was low.Total WSII were 19.54μg/m^(3)and 11.17μg/m^(3),accounting for 2.90%and 7.25%of the PM_(10)and PM_(2.5),respectively.In addition,the proportion of S-containing individual mineral dust was low(28.7%-35.3%).The results suggested there were limited secondary inorganic aerosol formation.However,when the dust was transported back to the sampling site across the Bohai Sea in the following days(reverse transport stages),both the PM_(10)mass concentrations(462.3μg/m^(3))and RH were high.Total WSII were 43.75μg/m^(3)and 18.71μg/m^(3),accounting for 9.62%and 14.45%of the total PM_(10)and PM_(2.5),respectively.The proportion of S-containing particles was 51.5%-72.5%.In addition,the concentration of NO_(3)^(−)was much higher than that of SO_(4)^(2−).The results suggested both the sulfate and nitrate formation occurred on coarse mineral dust but the nitrate formation exceeded sulfate formation.Interestingly,mostmineral dust,including Sirich particles contained Cl when they passed through the marine atmosphere.The results highlighted the heterogeneous reactions of dust varied in different transport stages.展开更多
Recent observations of Asian dust storms show an eastern expansion of the source area to degraded lands, where dust emissions have been little studied. The dust concentrations over the saline land of the western Songn...Recent observations of Asian dust storms show an eastern expansion of the source area to degraded lands, where dust emissions have been little studied. The dust concentrations over the saline land of the western Songnen Plain （SSL）, Northeastern China, are circumstantially higher than those from the northwestern Chinese deserts. These concentrations are sensitive to the surface soil conditions and wind velocity on the ground. The dust samples collected during dust storm events on the SSL contain abundant Na, Mg, A1, K, Ca, Fe and Ti, as well as toxic elements such as Cu, V, Zn and Ba. Individual particle analysis reveals that fine saline particles （〈 10 μm in diameter） on the saline land, consisting largely of carbonate, halite and sulfate together with lithogenic minerals such as SiO2 and aluminosilicate, are eventually uplifted during the interval from spring to autuum. The predominantly fine saline particles uplifted from the SSL are likely transported eastward by the winter monsoon circulation and westerlies. Recent degradation of saline lands in Northeastern China would not only increase the frequency of dust storm events in the downwind area, but also might change the chemical composition of the Asian dust emissions.展开更多
Quantities characterizing temporal property, e.g., power density, coherence, and time lag, can be defined and calculated directly in the time domain without using the Fourier transformation. Spectral hardness, variab...Quantities characterizing temporal property, e.g., power density, coherence, and time lag, can be defined and calculated directly in the time domain without using the Fourier transformation. Spectral hardness, variability duration, and correlation between different characteristic quamtities on different time scale can be studied in the time domain as well. The temporal analysis technique in the time domain is a powerful tool, particularly in studying rapid variability on short time scales (or in high frequencies). Results of studying variabilities of X-rays from Cyg X-1 with the analysis technique in the time domain and RXTE data reveal valuable clues to understanding production and propagation processes of X-rays and structure of accretion disk in the black hole system.展开更多
Modern methods of spectral estimation based on parametric time-series models are useful tools in power spectral analysis. We apply the autoregressive （AR） model to study quasi-periodic oscillations （QPOs）. An empi...Modern methods of spectral estimation based on parametric time-series models are useful tools in power spectral analysis. We apply the autoregressive （AR） model to study quasi-periodic oscillations （QPOs）. An empirical formula to estimate the expectation and standard deviation of the noise AR power densities is derived, which can be used to estimate the statistical significance of an apparent QPO peak in an AR spectrum. An iterative adding-noise algorithm in AR spectral analysis is proposed and applied to studying QPOs in the X-ray binary Cir X-1.展开更多
In order to further understand the sources of PM2.5 in Shanghai air, the synchrotron X-ray fluores- cence microprobe at the BL-4A Beamline of Photon Factory of High Energy Accelerator Research Organization, Japan, was...In order to further understand the sources of PM2.5 in Shanghai air, the synchrotron X-ray fluores- cence microprobe at the BL-4A Beamline of Photon Factory of High Energy Accelerator Research Organization, Japan, was applied to analyze the individual PM2.5 particles collected from Shanghai air in the winter of 2007. Eight categories of emission sources were recognized in these individual particles. The source identification shows that most of the analyzed PM2.5 particles are derived from vehicle exhaust and metallurgical emissions. This suggests that the important emission sources of PM2.5 in Shanghai air would be vehicle exhaust and metallurgical activities.展开更多
Background The efficacy of percutaneous transluminal angioplasty and stenting(PTAS)relative to medical management in treating symptomatic intracranial arterial stenosis(ICAS)varies based on the qualifying artery.This ...Background The efficacy of percutaneous transluminal angioplasty and stenting(PTAS)relative to medical management in treating symptomatic intracranial arterial stenosis(ICAS)varies based on the qualifying artery.This study aims to evaluate PTAS compared with medical therapy alone in cases of ICAS involving the internal carotid artery(ICA),middle cerebral artery(MCA),vertebral artery(VA)and basilar artery(BA).Methods This study involves a thorough pooled analysis of individual patient data from two randomised controlled trials,evaluating the efficacy of PTAS in comparison to medical management for symptomatic ICAS with different qualifying arteries.The primary outcome was stroke or death within 30 days postenrolment,or stroke in the region of the qualifying artery beyond 30 days through 1 year.A methodology based on intention-to-treat was employed,and HR accompanied by 95%CIs were used to convey risk estimates.Results The data of 809 individuals were collected from Stenting vs Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis trial and China Angioplasty and Stenting for Symptomatic Intracranial Severe Stenosis trial.Four hundred were designated for PTAS,while 409 were assigned to medical therapy alone.For the primary outcome,patients with symptomatic BA stenosis had a significantly higher risk of receiving PTAS compared with medical therapy(17.17%vs 7.77%;9.40;HR,2.38(1.03 to 5.52);p=0.04).However,PTAS had no significant difference in patients with symptomatic ICA(26.67%vs 16.67%;HR,1.68(0.78 to 3.62);p=0.19),MCA(8.28%vs 9.79%;HR,0.85(0.42 to 1.74);p=0.66)and VA stenosis(9.52%vs 10.71%;HR,0.91(0.32 to 2.62);p=0.86)compared with medical therapy.Conclusions PTAS significantly increases the risk of both short-term and long-term stroke in patients with symptomatic BA stenosis.Without significant technological advancements to mitigate these risks,PTAS offers limited benefits.For symptomatic ICA,MCA and VA stenosis,PTAS provided no significant advantage.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 10675023,11075018,11375028 and 11675020the Specialized Research Fund for the Doctoral Program of Higher Education under Grant No 20120003110011
文摘The radiation damage of three individual subcells for GalnP/GaAs//Ge triple-junction solar cells irradiated with electrons and protons is investigated using photoluminescence (PL) measurements. The PL spectra of each subcell are obtained using different excitation lasers. The PL intensity has a fast degradation after irradiation, and decreases as the displacement damage dose increases. Furthermore, the normalized PL intensity varying with the displacement damage dose is analyzed in detail, and then the lifetime damage coefficients of the recombination centers for GaInP top-cell, GaAs mid-cell and Ge bottom-cell of the triple-junction solar cells are determined from the PL radiative efficiency.
文摘Multiple BAC-FISH is a powerful tool for modern cytogenetic researching in both animals and plants.But in cotton,this technique is unavailable due to the high percentage of repetitive sequences.
基金The National Natural Science Foundation of China（No.40275040） and the Shanghai Leading Academic Disciplines（No. T0105）
文摘This work mainly focuses on the mineralogical study of particulate matter（PM10） in Beijing. Samples were collected on polycarbonate filter from April, 2002 to March, 2003 in Beijing urban area. Scanning electronic microscopy coupled with energy dispersive X-ray（SEM/EDX） was used to investigate individual mineral particles in Beijing PM10. 1454 individual mineral particulates from 48 samples were analysed by SEM/EDX. The results revealed that mineral particulates were complex and heterogeneous. 38 kinds of minerals in PM10 were identified. The clay minerals, of annual average percentage of 30.1%, were the main composition among the identified minerals, and illite/smectite was the main composition in clay minerals, reaching up to 35%. Annual average percentage of quartz, calcite, compound particulates, carbonates were 13.5%, 10.9%, 11.95%, 10.31%, respectively. Annual average percentage less than 10% were gypsum, feldspar, dolomite, and so on. Fluorite, apatite, halite, barite and chloridize zinc（ZnCl2） were firstly identified in Beijing PM10. Sulfurization was found on surface of mineral particles, suggested extensive atmospheric reaction in air during summer.
基金supported by the National Natural Science Foundation of China (Grant No.10633010)the University of Michigan Radio Astronomy Observatory,which has been supported by the University of Michigan and the Nationa Science Foundation
文摘We analyze the radio spectral index of blazars from the University of Michigan Radio Astronomy Observatory database,and find that there exists quasiperiodic activity in 2251＋158.The long-term periodicity analysis is accomplished by three methods,which are the Jurkevich method（Jurkevich）,the discrete correlation function（DCF）,and the Periodogram method（P）.The results show that 2251＋158 has two strong periodicities,which are P1=6.3±1.1 yr and P2=3.8±1.2 yr.
基金supported by the Natural Science Foundation of Hebei Province(Nos.B2022407001 and D2021501004)the National Natural Science Foundation of China(No.42075107)the Fundamental Research Funds for the Central Universities(No.N2223011).
文摘An intense Asian dust storm invadedQinhuangdao,a coastal city ofNorth China on April 11-14,2023.We analyzed the bulk water-soluble inorganic ions(WSII)of PM_(10)and PM_(2.5)using an Ion Chromatograph and investigated individual particlemorphology and elemental composition using a scanning electron microscope coupled with energy dispersive X-ray.The results showed when the dust was directly transported to the sampling site from northwestern China(direct transport stages),the PM_(10)mass concentrations were high(675.0μg/m^(3))but the relative humidity(RH)was low.Total WSII were 19.54μg/m^(3)and 11.17μg/m^(3),accounting for 2.90%and 7.25%of the PM_(10)and PM_(2.5),respectively.In addition,the proportion of S-containing individual mineral dust was low(28.7%-35.3%).The results suggested there were limited secondary inorganic aerosol formation.However,when the dust was transported back to the sampling site across the Bohai Sea in the following days(reverse transport stages),both the PM_(10)mass concentrations(462.3μg/m^(3))and RH were high.Total WSII were 43.75μg/m^(3)and 18.71μg/m^(3),accounting for 9.62%and 14.45%of the total PM_(10)and PM_(2.5),respectively.The proportion of S-containing particles was 51.5%-72.5%.In addition,the concentration of NO_(3)^(−)was much higher than that of SO_(4)^(2−).The results suggested both the sulfate and nitrate formation occurred on coarse mineral dust but the nitrate formation exceeded sulfate formation.Interestingly,mostmineral dust,including Sirich particles contained Cl when they passed through the marine atmosphere.The results highlighted the heterogeneous reactions of dust varied in different transport stages.
基金supported in a part by Chinese National Key Project of Basic Research (No G2000048703)the Grant-in-Aid for Scientific Research (No 16310008,18403002) from the Ministry of Education, Culture,Sports, Science and Technology, Japan
文摘Recent observations of Asian dust storms show an eastern expansion of the source area to degraded lands, where dust emissions have been little studied. The dust concentrations over the saline land of the western Songnen Plain （SSL）, Northeastern China, are circumstantially higher than those from the northwestern Chinese deserts. These concentrations are sensitive to the surface soil conditions and wind velocity on the ground. The dust samples collected during dust storm events on the SSL contain abundant Na, Mg, A1, K, Ca, Fe and Ti, as well as toxic elements such as Cu, V, Zn and Ba. Individual particle analysis reveals that fine saline particles （〈 10 μm in diameter） on the saline land, consisting largely of carbonate, halite and sulfate together with lithogenic minerals such as SiO2 and aluminosilicate, are eventually uplifted during the interval from spring to autuum. The predominantly fine saline particles uplifted from the SSL are likely transported eastward by the winter monsoon circulation and westerlies. Recent degradation of saline lands in Northeastern China would not only increase the frequency of dust storm events in the downwind area, but also might change the chemical composition of the Asian dust emissions.
基金the Special Funds for Major State Basic Research Projects and by the National Natural Science Foundation of China
文摘Quantities characterizing temporal property, e.g., power density, coherence, and time lag, can be defined and calculated directly in the time domain without using the Fourier transformation. Spectral hardness, variability duration, and correlation between different characteristic quamtities on different time scale can be studied in the time domain as well. The temporal analysis technique in the time domain is a powerful tool, particularly in studying rapid variability on short time scales (or in high frequencies). Results of studying variabilities of X-rays from Cyg X-1 with the analysis technique in the time domain and RXTE data reveal valuable clues to understanding production and propagation processes of X-rays and structure of accretion disk in the black hole system.
基金Supported by the National Natural Science Foundation of China and by the State Basic Science Research Projects of China.
文摘Modern methods of spectral estimation based on parametric time-series models are useful tools in power spectral analysis. We apply the autoregressive （AR） model to study quasi-periodic oscillations （QPOs）. An empirical formula to estimate the expectation and standard deviation of the noise AR power densities is derived, which can be used to estimate the statistical significance of an apparent QPO peak in an AR spectrum. An iterative adding-noise algorithm in AR spectral analysis is proposed and applied to studying QPOs in the X-ray binary Cir X-1.
基金Supported by Knowledge Innovation Project of Chinese Academy of Sciences (KJCX3.SYW.N3) National Natural Science Foundation of China (10775172, 10675159)performance under approval of Photon Factory (PF) Program Advisory Committee(Proposal No.2007G502)
文摘In order to further understand the sources of PM2.5 in Shanghai air, the synchrotron X-ray fluores- cence microprobe at the BL-4A Beamline of Photon Factory of High Energy Accelerator Research Organization, Japan, was applied to analyze the individual PM2.5 particles collected from Shanghai air in the winter of 2007. Eight categories of emission sources were recognized in these individual particles. The source identification shows that most of the analyzed PM2.5 particles are derived from vehicle exhaust and metallurgical emissions. This suggests that the important emission sources of PM2.5 in Shanghai air would be vehicle exhaust and metallurgical activities.
基金Beijing Hospitals Authority’s Ascent Plan(DFL20220702)National Natural Science Foundation of China(82101398).
文摘Background The efficacy of percutaneous transluminal angioplasty and stenting(PTAS)relative to medical management in treating symptomatic intracranial arterial stenosis(ICAS)varies based on the qualifying artery.This study aims to evaluate PTAS compared with medical therapy alone in cases of ICAS involving the internal carotid artery(ICA),middle cerebral artery(MCA),vertebral artery(VA)and basilar artery(BA).Methods This study involves a thorough pooled analysis of individual patient data from two randomised controlled trials,evaluating the efficacy of PTAS in comparison to medical management for symptomatic ICAS with different qualifying arteries.The primary outcome was stroke or death within 30 days postenrolment,or stroke in the region of the qualifying artery beyond 30 days through 1 year.A methodology based on intention-to-treat was employed,and HR accompanied by 95%CIs were used to convey risk estimates.Results The data of 809 individuals were collected from Stenting vs Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis trial and China Angioplasty and Stenting for Symptomatic Intracranial Severe Stenosis trial.Four hundred were designated for PTAS,while 409 were assigned to medical therapy alone.For the primary outcome,patients with symptomatic BA stenosis had a significantly higher risk of receiving PTAS compared with medical therapy(17.17%vs 7.77%;9.40;HR,2.38(1.03 to 5.52);p=0.04).However,PTAS had no significant difference in patients with symptomatic ICA(26.67%vs 16.67%;HR,1.68(0.78 to 3.62);p=0.19),MCA(8.28%vs 9.79%;HR,0.85(0.42 to 1.74);p=0.66)and VA stenosis(9.52%vs 10.71%;HR,0.91(0.32 to 2.62);p=0.86)compared with medical therapy.Conclusions PTAS significantly increases the risk of both short-term and long-term stroke in patients with symptomatic BA stenosis.Without significant technological advancements to mitigate these risks,PTAS offers limited benefits.For symptomatic ICA,MCA and VA stenosis,PTAS provided no significant advantage.
