查看更多>>摘要：Efficient detection of single optical centres in solids is essential for quantum information processing,sensing and single-photon generation applications.In this work,we use radio-frequency(RF)reflectometry to electrically detect the photoionisation induced by a single Er3+ion in Si.The high bandwidth and sensitivity of the RF reflectometry provide sub-100-ns time resolution for the photoionisation detection.With this technique,the optically excited state lifetime of a single Er3+ion in a Si nano-transistor is measured for the first time to be 0.49±0.04 μs.Our results demonstrate an efficient approach for detecting a charge state change induced by Er excitation and relaxation.This approach could be used for fast readout of other single optical centres in solids and is attractive for large-scale integrated optical quantum systems thanks to the multi-channel RF reflectometry demonstrated with frequency multiplexing techniques.
查看更多>>摘要：The memristor is the building block of neuromorphic computing.We report a new type of nanofluidic memristor based on the principle of elastic strain on polymer nanopores.With nanoparticles absorbed at the wall of a single conical polymer nanopore,we find a pinched hysteresis of the current within a scanning frequency range of 0.01-0.1 Hz,switching to a diode below 0.01 Hz and a resistor above 0.1 Hz.We attribute the current hysteresis to the elastic strain at the tip side of the nanopore,caused by electrical force on the particles adsorbed at the inner wall surface.Our simulation and analytical equations match well with experimental results,with a phase diagram for predicting the system transitions.We demonstrate the plasticity of our nanofluidic memristor to be similar to a biological synapse.Our findings pave a new way for ionic neuromorphic computing using nanofluidic memristors.
查看更多>>摘要：For sessile plants,gene expression plays a pivotal role in responding to salinity stress by activating or suppressing specific genes.However,our knowledge of genetic variations governing gene expression in response to salt stress remains limited in natural germplasm.Through transcriptome analysis of the Global Mini-Core Rice Collection consisting of a panel of 202 accessions,we identified 22 345 and 27 610 expression quantitative trait loci associated with the expression of 7787 and 9361 eGenes under normal and salt-stress conditions,respectively,leveraging the super pan-genome map.Notably,combined with genome-wide association studies,we swiftly pinpointed the potential candidate gene STG5—a major salt-tolerant locus known as qSTS5.Intriguingly,STG5 is required for maintaining Na+/K+homeostasis by directly regulating the transcription of multiple members of the OsHKT gene family.Our study sheds light on how genetic variants influence the dynamic changes in gene expression responding to salinity stress and provides a valuable resource for the mining of salt-tolerant genes in the future.
查看更多>>摘要：The nucleus of Darkschewitsch(ND),mainly composed of GABAergic neurons,is widely recognized as a component of the eye-movement controlling system.However,the functional contribution of ND GABAergic neurons(NDGABA)in animal behavior is largely unknown.Here,we show that NDGABA neurons were selectively activated by different types of fear stimuli,such as predator odor and foot shock.Optogenetic and chemogenetic manipulations revealed that NDGABA neurons mediate freezing behavior.Moreover,using circuit-based optogenetic and neuroanatomical tracing methods,we identified an excitatory pathway from the lateral periaqueductal gray(1PAG)to the ND that induces freezing by exciting ND inhibitory outputs to the motor-related gigantocellular reticular nucleus,ventral part(GiV).Together,these findings indicate the NDGABA population as a novel hub for controlling defensive response by relaying fearful information from the 1PAG to GiV,a mechanism critical for understanding how the freezing behavior is encoded in the mammalian brain.
查看更多>>摘要：China currently has the highest acid deposition globally,yet research on its status,impacts,causes and controls is lacking.Here,we compiled data and calculated critical loads regarding acid deposition.The results showed that the abatement measures in China have achieved a sharp decline in the emissions of acidifying pollutants and a continuous recovery of precipitation pH,despite the drastic growth in the economy and energy consumption.However,the risk of ecological acidification and eutrophication showed no significant decrease.With similar emission reductions,the decline in areas at risk of acidification in China(7.0％)lags behind those in Europe(20％)or the USA(15％).This was because,unlike Europe and the USA,China's abatement strategies primarily target air quality improvement rather than mitigating ecological impacts.Given that the area with the risk of eutrophication induced by nitrogen deposition remained at 13％of the country even under the scenario of achieving the dual targets of air quality and carbon dioxide mitigation in 2035,we explored an enhanced ammonia abatement pathway.With a further 27％reduction in ammonia by 2035,China could largely eliminate the impacts of acid deposition.This research serves as a valuable reference for China's future acid deposition control and for other nations facing similar challenges.
查看更多>>摘要：Tropospheric reactive bromine is important for atmospheric chemistry,regional air pollution,and global climate.Previous studies have reported measurements of atmospheric reactive bromine species in different environments,and proposed their main sources,e.g.sea-salt aerosol(SSA),oceanic biogenic activity,polar snow/ice,and volcanoes.Typhoons and other strong cyclonic activities(e.g.hurricanes)induce abrupt changes in different earth system processes,causing widespread destructive effects.However,the role of typhoons in regulating reactive bromine abundance and sources remains unexplored.Here,we report field observations of bromine oxide(BrO),a critical indicator of reactive bromine,on the Huaniao Island(HNI)in the East China Sea in July 2018.We observed high levels of BrO below 500 m with a daytime average of 9.7±4.2 pptv and a peak value of～26 pptv under the influence of a typhoon.Our field measurements,supported by model simulations,suggest that the typhoon-induced drastic increase in wind speed amplifies the emission of SSA,significantly enhancing the activation of reactive bromine from SSA debromination.We also detected enhanced BrO mixing ratios under high NOx conditions(ppbv level)suggesting a potential pollution-induced mechanism of bromine release from SSA.Such elevated levels of atmospheric bromine noticeably increase ozone destruction by as much as～40％across the East China Sea.Considering the high frequency of cyclonic activity in the northern hemisphere,reactive bromine chemistry is expected to play a more important role than previously thought in affecting coastal air quality and atmospheric oxidation capacity.We suggest that models need to consider the hitherto overlooked typhoon-and pollution-mediated increase in reactive bromine levels when assessing the synergic effects of cyclonic activities on the earth system.
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