Multiple-Input Multiple-Output (MIMO) technology is widely applied in terrestrial wireless communication system, which greatly increases the system capacity. Satellite communication system has many advantages such as ...Multiple-Input Multiple-Output (MIMO) technology is widely applied in terrestrial wireless communication system, which greatly increases the system capacity. Satellite communication system has many advantages such as wide coverage and strong flexibility. Therefore, how to make a better use of MIMO technology in satellite communication system has become a research hotspot in recent years. The purpose of this paper is to analysis the relationship between satellite MIMO system capacity and parameters of terrestrial antenna such as angle and distance. The parameters of terrestrial antenna were derived and calculated to keep a higher capacity for satellite MIMO system. Numerical analysis of system capacity performance before and after optimization was obtained, which proved the correctness of the theory proposed in this paper.展开更多
Recent baby formula milk powder contamination incidents have shown that the classic markers or standards in milk quality control are insufficient in identifying ＂manipulated＂ poor-quality milk. In the present study,...Recent baby formula milk powder contamination incidents have shown that the classic markers or standards in milk quality control are insufficient in identifying ＂manipulated＂ poor-quality milk. In the present study, we demonstrated for the first time that cow milk contains large amounts of microRNAs （miRNAs） and that the unique expression profile of milk-specific miRNAs can serve as a novel indicator and possible new standard for the quafity control of raw milk and milk-related commercial products, such as fluid milk and powdered formula milk. First, using Solexa sequencing, we systematically screened miRNA expression in raw milk and identified a total of 245 miR- NAs in raw milk. Unlike other classic biomarkers whose expression levels are nearly identical at different periods of lactation, individual miRNAs can be significantly altered during lactation process, implicating that miRNAs may be a more accurate indicator to reflect the quality alteration of milk. Second, using TaqMan probe-based miRNA quantitative RT-PCR, we further identified seven miRNAs that have a relatively consistent expression throughout the lactation process, and more importantly, the expression profile of these seven milk-specific miRNAs can serve as an ideal biomarker for discriminating poor-quality or ＂manipulated＂ milk from pure raw milk, as well as for the quality control of commercial milk products, such as fluid milk and powdered formula milk. Together, our findings provide a basis for understanding the physiological role of milk miRNAs and a new potential standard for determining the quality of raw milk or milk-related commercial products.展开更多
Electron transport layer(ETL)is very critical to the performance of perovskite solar cells(PSCs),and optimization work on ETL has received extensive attentions especially on tin oxide(SnO_(2))since it is an excellent ...Electron transport layer(ETL)is very critical to the performance of perovskite solar cells(PSCs),and optimization work on ETL has received extensive attentions especially on tin oxide(SnO_(2))since it is an excellent ETL material widely applied in high-efficiency PSCs.Thereinto,introducing mesoporous structure and surface modification are two important approaches which are commonly applied.Herein,based on the previous work in low-temperature fabrication process of mesoporous SnO_(2)(mSnO_(2)),we introduced a modification process with rubidium fuoride(Rb F)to the m-SnO_(2)ETL,and successfully achieved a synergy of the m-SnO_(2)and Rb F modification:not only the shortcoming of the m-SnO_(2)in interfacial traps was overcome,but also the carrier collection efficiency was further improved.The PSCs based on the m-SnO_(2)ETL with Rb F modification demonstrated outstanding performances:a champion power conversion efficiency(PCE)of 22.72%and a stability performance of maintaining 90%of the initial PCE after 300 h of MPP tracking were obtained without surface passivation of perovskite film.Hence,utilizing the abovementioned synergy is a cost-effective and feasible strategy for fabricating high-efficiency and stable PSCs since the fabrication process of the m-SnO_(2)ETL is a kind of low temperature process and RbF is cheap.展开更多
The triple cation mixed perovskites(Cs FAMA)are known as one of the most efficient candidates for perovskite solar cells(PSCs).It is found that the power conversion efficiency(PCE)of triple-cation based devices would ...The triple cation mixed perovskites(Cs FAMA)are known as one of the most efficient candidates for perovskite solar cells(PSCs).It is found that the power conversion efficiency(PCE)of triple-cation based devices would increase with the test time extending,and the maximum efficiency is normally obtained after several days aging storage.Here,the relationship between enhanced device performance,excess PbI_(2)and its evolution in triple cation perovskite films of initial days was systematically explored.The Cs FAMA-PSCs are prepared by two-step methods under two environmental conditions,including in the glove box and the ambient air(30%humidity).After 7 days testing,the maximum PCE of PSCs under two conditions dramatically increased 12.4%and 12.2%,reached 21.68%and 21.89%,respectively.At initial days,the XRD peak intensities of perovskite phase gradually decreased and those corresponding to PbI_(2)increased.Along with time-resolved photoluminescence(TRPL)and kelvin probe force microscopy(KPFM),it was found that the defects were passivated with the evolution of PbI_(2).This work reveals the excess PbI_(2)and its evolution in perovskite film,which can further supplement the understanding of PbI_(2)defect passivation.展开更多
The aging-induced performance enhancement of the perovskite solar cells(PSCs)has been considered to be associated with the oxidation progress of the hole-transporting layer.Whereas the influence of the structural evol...The aging-induced performance enhancement of the perovskite solar cells(PSCs)has been considered to be associated with the oxidation progress of the hole-transporting layer.Whereas the influence of the structural evolution of the passivation layer is underestimated.In this work,a spontaneous relaxation of two-dimensional(2D)passivation layer with increased n-value structure is observed,which can be accelerated under ambient atmosphere.It is demonstrated that device with relaxed 2D passivation layer exhibits reduced non-radiative recombination and optimized charge transfer property,contributing substantially to the aging-induced performance enhancement in 2D-3D heterostructured PSCs.Finally,a high fill factor of 84.15%of the devices is obtained with the relaxed 2D passivation layer,suggesting the spontaneous relaxation of 2D passivation layer is playing a key role in achieving high quality optoelectronic devices.展开更多
The High Altitude Detection of Astronomical Radiation(HADAR)experiment is a refracting terrestrial telescope array based on the atmospheric Cherenkov imaging technique.It focuses the Cherenkov light emitted by extensi...The High Altitude Detection of Astronomical Radiation(HADAR)experiment is a refracting terrestrial telescope array based on the atmospheric Cherenkov imaging technique.It focuses the Cherenkov light emitted by extensive air showers through a large aperture water-lens system for observing very-high-energyγ-rays and cosmic rays.With the advantages of a large field-of-view(FOV)and low energy threshold,the HADAR experiment operates in a large-scale sky scanning mode to observe galactic sources.This study presents the prospects of using the HADAR experiment for the sky survey of TeVγ-ray sources from TeVCat and provids a one-year survey of statistical significance.Results from the simulation show that a total of 23 galactic point sources,including five supernova remnant sources and superbubbles,four pulsar wind nebula sources,and 14 unidentified sources,were detected in the HADAR FOV with a significance greater than 5 standard deviations(σ).The statistical significance for the Crab Nebula during one year of operation reached 346.0σand the one-year integral sensitivity of HADAR above 1 TeV was~1.3%–2.4%of the flux from the Crab Nebula.展开更多
文摘Multiple-Input Multiple-Output (MIMO) technology is widely applied in terrestrial wireless communication system, which greatly increases the system capacity. Satellite communication system has many advantages such as wide coverage and strong flexibility. Therefore, how to make a better use of MIMO technology in satellite communication system has become a research hotspot in recent years. The purpose of this paper is to analysis the relationship between satellite MIMO system capacity and parameters of terrestrial antenna such as angle and distance. The parameters of terrestrial antenna were derived and calculated to keep a higher capacity for satellite MIMO system. Numerical analysis of system capacity performance before and after optimization was obtained, which proved the correctness of the theory proposed in this paper.
基金This work was supported by grants from the National Natural Science Foundation of China （30225037, 30471991, 30570731）, the 973 Program of China （2006CB503909, 2004CB518603）, the ＂111＂ Project, and the Natural Science Foundation of Jiangsu Province （BK2004082, BIC2006714）.
文摘Recent baby formula milk powder contamination incidents have shown that the classic markers or standards in milk quality control are insufficient in identifying ＂manipulated＂ poor-quality milk. In the present study, we demonstrated for the first time that cow milk contains large amounts of microRNAs （miRNAs） and that the unique expression profile of milk-specific miRNAs can serve as a novel indicator and possible new standard for the quafity control of raw milk and milk-related commercial products, such as fluid milk and powdered formula milk. First, using Solexa sequencing, we systematically screened miRNA expression in raw milk and identified a total of 245 miR- NAs in raw milk. Unlike other classic biomarkers whose expression levels are nearly identical at different periods of lactation, individual miRNAs can be significantly altered during lactation process, implicating that miRNAs may be a more accurate indicator to reflect the quality alteration of milk. Second, using TaqMan probe-based miRNA quantitative RT-PCR, we further identified seven miRNAs that have a relatively consistent expression throughout the lactation process, and more importantly, the expression profile of these seven milk-specific miRNAs can serve as an ideal biomarker for discriminating poor-quality or ＂manipulated＂ milk from pure raw milk, as well as for the quality control of commercial milk products, such as fluid milk and powdered formula milk. Together, our findings provide a basis for understanding the physiological role of milk miRNAs and a new potential standard for determining the quality of raw milk or milk-related commercial products.
基金mainly supported by the operational funds of Institute of Photovoltaic,Southwest Petroleum University and Sichuan Science and Technology Program(2018JY0015)。
文摘Electron transport layer(ETL)is very critical to the performance of perovskite solar cells(PSCs),and optimization work on ETL has received extensive attentions especially on tin oxide(SnO_(2))since it is an excellent ETL material widely applied in high-efficiency PSCs.Thereinto,introducing mesoporous structure and surface modification are two important approaches which are commonly applied.Herein,based on the previous work in low-temperature fabrication process of mesoporous SnO_(2)(mSnO_(2)),we introduced a modification process with rubidium fuoride(Rb F)to the m-SnO_(2)ETL,and successfully achieved a synergy of the m-SnO_(2)and Rb F modification:not only the shortcoming of the m-SnO_(2)in interfacial traps was overcome,but also the carrier collection efficiency was further improved.The PSCs based on the m-SnO_(2)ETL with Rb F modification demonstrated outstanding performances:a champion power conversion efficiency(PCE)of 22.72%and a stability performance of maintaining 90%of the initial PCE after 300 h of MPP tracking were obtained without surface passivation of perovskite film.Hence,utilizing the abovementioned synergy is a cost-effective and feasible strategy for fabricating high-efficiency and stable PSCs since the fabrication process of the m-SnO_(2)ETL is a kind of low temperature process and RbF is cheap.
基金the financial support from the Young Scholars Development Fund of SWPU(201699010017)the Sichuan Science and Technology Program(2018JY0015)+1 种基金the National Nature Science Foundation of China(61774022)the 2020 Li Ka Shing Foundation Cross-Disciplinary Research Grant(2020LKSFG01A)。
文摘The triple cation mixed perovskites(Cs FAMA)are known as one of the most efficient candidates for perovskite solar cells(PSCs).It is found that the power conversion efficiency(PCE)of triple-cation based devices would increase with the test time extending,and the maximum efficiency is normally obtained after several days aging storage.Here,the relationship between enhanced device performance,excess PbI_(2)and its evolution in triple cation perovskite films of initial days was systematically explored.The Cs FAMA-PSCs are prepared by two-step methods under two environmental conditions,including in the glove box and the ambient air(30%humidity).After 7 days testing,the maximum PCE of PSCs under two conditions dramatically increased 12.4%and 12.2%,reached 21.68%and 21.89%,respectively.At initial days,the XRD peak intensities of perovskite phase gradually decreased and those corresponding to PbI_(2)increased.Along with time-resolved photoluminescence(TRPL)and kelvin probe force microscopy(KPFM),it was found that the defects were passivated with the evolution of PbI_(2).This work reveals the excess PbI_(2)and its evolution in perovskite film,which can further supplement the understanding of PbI_(2)defect passivation.
基金M.Z.acknowledges the Sichuan Science and Technology Program(No.2022YFH0080)This work was also supported by scientific research starting project of SWPU(Nos.2021QHZ005 and 2021QHZ021).
文摘The aging-induced performance enhancement of the perovskite solar cells(PSCs)has been considered to be associated with the oxidation progress of the hole-transporting layer.Whereas the influence of the structural evolution of the passivation layer is underestimated.In this work,a spontaneous relaxation of two-dimensional(2D)passivation layer with increased n-value structure is observed,which can be accelerated under ambient atmosphere.It is demonstrated that device with relaxed 2D passivation layer exhibits reduced non-radiative recombination and optimized charge transfer property,contributing substantially to the aging-induced performance enhancement in 2D-3D heterostructured PSCs.Finally,a high fill factor of 84.15%of the devices is obtained with the relaxed 2D passivation layer,suggesting the spontaneous relaxation of 2D passivation layer is playing a key role in achieving high quality optoelectronic devices.
基金support from the National Natural Science Foundation of China(Nos.11873005,11705103,12005120,12147218,U1831208,U1632104,11875264,and U2031110).
文摘The High Altitude Detection of Astronomical Radiation(HADAR)experiment is a refracting terrestrial telescope array based on the atmospheric Cherenkov imaging technique.It focuses the Cherenkov light emitted by extensive air showers through a large aperture water-lens system for observing very-high-energyγ-rays and cosmic rays.With the advantages of a large field-of-view(FOV)and low energy threshold,the HADAR experiment operates in a large-scale sky scanning mode to observe galactic sources.This study presents the prospects of using the HADAR experiment for the sky survey of TeVγ-ray sources from TeVCat and provids a one-year survey of statistical significance.Results from the simulation show that a total of 23 galactic point sources,including five supernova remnant sources and superbubbles,four pulsar wind nebula sources,and 14 unidentified sources,were detected in the HADAR FOV with a significance greater than 5 standard deviations(σ).The statistical significance for the Crab Nebula during one year of operation reached 346.0σand the one-year integral sensitivity of HADAR above 1 TeV was~1.3%–2.4%of the flux from the Crab Nebula.
