The use of broadband laser technology is a novel approach for inhibiting processes related to laser plasma interactions(LPIs).In this study,several preliminary experiments into broadband-laser-driven LPIs are carried ...The use of broadband laser technology is a novel approach for inhibiting processes related to laser plasma interactions(LPIs).In this study,several preliminary experiments into broadband-laser-driven LPIs are carried out using a newly established hundreds-of-joules broadband second-harmonic-generation laser facility.Through direct comparison with LPI results for a traditional narrowband laser,the actual LPI-suppression effect of the broadband laser is shown.The broadband laser had a clear suppressive effect on both back-stimulated Raman scattering and back-stimulated Brillouin scattering at laser intensities below 1×10^(15) W cm^(−2).An abnormal hot-electron phenomenon is also investigated,using targets of different thicknesses.展开更多
Western diet(rich in highly refined sugar and fat)can induce a range of metabolic dysfunctions in animals and humans,including neuroinflammation and cognitive function decline.Neuroinflammation and cognitive impairmen...Western diet(rich in highly refined sugar and fat)can induce a range of metabolic dysfunctions in animals and humans,including neuroinflammation and cognitive function decline.Neuroinflammation and cognitive impairment,two critical pathological characteristics of Alzheimer’s disease,have been closely associated with microbial alteration via the gut-brain axis.Thus,the present study aimed to investigate the influence of 2-O-β-D-glucopyranosyl-L-ascorbic acid(AA-2βG)isolated from the fruits of Lycium barbarum on preventing the high-fructose diet(HFrD)induced neuroinflammation in mice.It was found that AA-2βG prevented HFr D-induced cognitive deficits.AA-2βG also predominantly enhanced the gut barrier integrity,decreased lipopolysaccharide entry into the circulation,which subsequently countered the activation of glial cells and neuroinflammatory response.These beneficial effects were transmissible by horizontal fecal microbiome transplantation,transferring from AA-2βG fed mice to HFr D fed mice.Additionally,AA-2βG exerted neuroprotective effects involving the enrichment of Lactobacillus and Akkermansia,potentially beneficial intestinal bacteria.The present study provided the evidence that AA-2βG could improve indices of cognition and neuroinflammmation via modulating gut dybiosis and preventing leaky gut.As a potential functional food ingredient,AA-2βG may be applied to attenuate neuroinflammation associated with Western-style diets.展开更多
The Zeeman splitting effect is observed in a strong magnetic field generated by a laser-driven coil.The expanding plasma from the coil wire surface is concentrated at the coil center and interacts with the simultaneou...The Zeeman splitting effect is observed in a strong magnetic field generated by a laser-driven coil.The expanding plasma from the coil wire surface is concentrated at the coil center and interacts with the simultaneously generated magnetic field.The Cu I spectral lines at wavelengths of 510.5541,515.3235,and 521.8202 nm are detected and analyzed.The splittings of spectral lines are used to estimate the magnetic field strength at the coil center as∼31.4±15.7 T at a laser intensity of∼5.6310^(15) W/cm^(2),which agrees well with measurements using a B-dot probe.Some other plasma parameters of the central plasma disk are also studied.The temperature is evaluated from the Cu I spectral line intensity ratio,while the electron density is estimated from the Stark broadening effect.展开更多
Heterodimerization in RTKs is of vital importance in the RTK signaling and cell functions.Heterodimerization between RTKs can result in diversity of downstream signals,increasing the ability of cells to respond to ext...Heterodimerization in RTKs is of vital importance in the RTK signaling and cell functions.Heterodimerization between RTKs can result in diversity of downstream signals,increasing the ability of cells to respond to external experiments.Traditional RTKs heterodimerization always occur in the same families and is lack of agonists to activate the heterodimeric RTKs signaling pathway.Herein,we developed the DNA agonist based on bivalent aptamers for the heterodimerized RTKs of different families,AF/AM-1,which could simultaneously activate FGFR1 and c-Met signaling.It is the first agonist that realizing the heterodimerization and activation of FGFR1 and c-Met,two different RTK families.The activation of FGFR1/c-Met heterodimer result in the down-stream signals transduction,such as the phosphorylation of Akt and Erk,inducing the cell migration and proliferation.The DNA agonist for RTK heterodimer of different families would have potential applications in the fields of biomedicine.展开更多
Cough is a vital defensive reflex for expelling harmful substances from the airway.The sensory afferents for the cough reflex have been intensively studied.However,the brain mechanisms underlying the cough reflex rema...Cough is a vital defensive reflex for expelling harmful substances from the airway.The sensory afferents for the cough reflex have been intensively studied.However,the brain mechanisms underlying the cough reflex remain poorly understood.Here,we developed a paradigm to quantitatively measure cough-like reflexes in mice.Using this paradigm,we found that prodynorphin-expressing(Pdyn+)neurons in the nucleus of the solitary tract(NTS)are critical for capsaicin-induced cough-like reflexes.These neurons receive cough-related neural signals from Trpv1+vagal sensory neurons.The activation of Pdyn+NTS neurons triggered respiratory responses resembling cough-like reflexes.Among the divergent projections of Pdyn+NTS neurons,a glutamatergic pathway projecting to the caudal ventral respiratory group(cVRG),the canonical cough center,was necessary and sufficient for capsaicin-induced cough-like reflexes.These results reveal that Pdyn+NTS neurons,as a key neuronal population at the entry point of the vagus nerve to the brainstem,initiate cough-like reflexes in mice.展开更多
Oxidation protective MoSi2-MosSi3/SiC multi-coatings for carbon/carbon composites were prepared by chemical vapor reaction and slurry-sintering method. The influence of preparation technology on the structure and phas...Oxidation protective MoSi2-MosSi3/SiC multi-coatings for carbon/carbon composites were prepared by chemical vapor reaction and slurry-sintering method. The influence of preparation technology on the structure and phase composition of the coating was investigated by scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS） and X-ray diffraction （XRD） analyses, and then their relationship was discussed. The results indicate that the Si/Mo ratio of the slurry and sintering processing were two main factors that significantly affected the structure and phase composition of the multi-coating. Appropriate sintering process and relatively high Si/Mo ratio were essential for preparing the multi-coating with dense structure and favorable phase composition. After being sintered at 1723 K for 2 h and with the Si/Mo ratio of the slurry being 4.5 （weight ratio）, a dense structure accompanied by favorable phase composition of the coating can be obtained. When heat treated at 2373 K for I h, this coating became more compact and continuous. Oxidation tests （performed at 1623 and 1823 K） demonstrated that both of these two obtained multi-coatings exhibited better anti-oxidation property than single layer SiC coating.展开更多
The distribution of polyfluoroalkyl compounds(PFCs)in the dissolved and particulate phase and their discharge from the river Elbe into the North Sea were studied.The PFCs quantified included C_(4)-C_(8) perfluorinated...The distribution of polyfluoroalkyl compounds(PFCs)in the dissolved and particulate phase and their discharge from the river Elbe into the North Sea were studied.The PFCs quantified included C_(4)-C_(8) perfluorinated sulfonates(PFSAs),6∶2 fluorotelomer sulfonate(6∶2 FTS),C_(6) and C_(8) perfluorinated sulfinates(PFSiAs),C_(4)-C_(12) perfluorinated carboxylic acids(PFCAs),perfluoro-3,7-dimethyl-octanoic acid(3,7m_(2)-PFOA),perfluorooctane sulfonamide(FOSA),and n-ethyl perfluroctane sulfonamidoethanol(EtFOSE).PFCs were mostly distributed in the dissolved phase,where perfluorooctanoic acid(PFOA)dominated with 2.9–12.5 ng/L.In the suspended particulate matter FOSA and perfluorooctane sulfonate(PFOS)showed the highest concentrations(4.0 ng/L and 2.3 ng/L,respectively).The total flux ofΣPFCs from the river Elbe was estimated to be 802 kg/year for the dissolved phase and 152 kg/year for the particulate phase.This indicates that the river Elbe acts as a source of PFCs into the North Sea.However,the concentrations of perfluorobutane sulfonate(PFBS)and perfluorobutanoic acid(PFBA)in the North Sea were higher than that in the river Elbe,thus an alternative source must exist for these compounds.展开更多
A new approach to target development for laboratory astrophysics experiments at high-power laser facilities is presented.With the dawn of high-power lasers,laboratory astrophysics has emerged as a field,bringing insig...A new approach to target development for laboratory astrophysics experiments at high-power laser facilities is presented.With the dawn of high-power lasers,laboratory astrophysics has emerged as a field,bringing insight into physical processes in astrophysical objects,such as the formation of stars.An important factor for success in these experiments is targetry.To date,targets have mainly relied on expensive and challenging microfabrication methods.The design presented incorporates replaceable machined parts that assemble into a structure that defines the experimental geometry.This can make targets cheaper and faster to manufacture,while maintaining robustness and reproducibility.The platform is intended for experiments on plasma flows,but it is flexible and may be adapted to the constraints of other experimental setups.Examples of targets used in experimental campaigns are shown,including a design for insertion in a high magnetic field coil.Experimental results are included,demonstrating the performance of the targets.展开更多
Trace metal(Cr, Ni, Cu, Zn, Cd and Pb) exposures, distribution and bioaccumulation were investigated in marine organisms from Guangdong coastal regions, South China. The results showed that all of the selected metals ...Trace metal(Cr, Ni, Cu, Zn, Cd and Pb) exposures, distribution and bioaccumulation were investigated in marine organisms from Guangdong coastal regions, South China. The results showed that all of the selected metals were observed in marine organisms with a predomination of Cu and Zn. The metal exposure levels exhibited obvious variations between species with the decreasing order of crab > shellfish > shrimp > fish. The higher metals enrichment seen in shellfish and crab species primarily attributed to their living habits and the higher sediment background values of trace metals. Endpoint bioaccumulation factor(BAFfd) was used to characterize the bioaccumulation potentials of marine organisms to trace metals, of which Cu and Zn were the most accumulated elements. The exposure of trace metals in the cultured organisms was far lower than those in wild marine organisms, which is probably due to the effect of growth dilution. Comparisons with previous studies demonstrated that the concentration profiles of most trace metals declined over the last one to two decades, except Cu, that increased indistinctively.展开更多
The mushroom body(MB),a bilateral brain structure pos-sessing about 2000-2500 neurons per hemisphere,plays a central role in olfactory learning and memory in Dros-ophila melanogaster.Extensive studies have demonstrat-...The mushroom body(MB),a bilateral brain structure pos-sessing about 2000-2500 neurons per hemisphere,plays a central role in olfactory learning and memory in Dros-ophila melanogaster.Extensive studies have demonstrat-ed that three major types of MB neurons(α/β,α’/β’andγ)exhibit distinct functions in memory processing,including the critical role of approximately 1000 MBα/βneurons in retrieving long-term memory.Inspired by recent fi ndings that MBα/βneurons can be further divided into three subdivisions(surface,posterior and core)and wherein theα/βcore neurons play an permissive role in long-term memory consolidation,we examined the functional differ-ences of all the three morphological subdivisions of MBα/βby temporally precise manipulation of their synaptic outputs during long-term memory retrieval.We found the normal neurotransmission from a combination of MBα/βsurface and posterior neurons is necessary for retrieving both aversive and appetitive long-term memory,whereas output from MBα/βposterior or core subdivision alone is dispensable.These results imply a specifi c requirement of about 500 MBα/βneurons in supporting long-term memory retrieval and a further functional partitioning for memory processing within the MBα/βregion.展开更多
A new crystal spectrometer for application in X-ray opacity experiments is proposed. The conditions necessary to yield broad spectral coverage with a resolution >500, strong rejection of hard X-ray backgrounds and ...A new crystal spectrometer for application in X-ray opacity experiments is proposed. The conditions necessary to yield broad spectral coverage with a resolution >500, strong rejection of hard X-ray backgrounds and negligible source broadening for extended sources are formulated. In addition, the design, response modeling and reporting of an elliptical crystal spectrometer in conjunction with a linear detector are presented. The measured results demonstrate the performance of the new crystal spectrometer with a broad energy coverage range, high spectral resolution, and high luminosity(good collection efficiency). This spectrometer can be used in combination with point-projection backlighting techniques as utilized in X-ray opacity experiments. Specifically, the X-ray source, transmission and self-emission spectra of the sample can be measured simultaneously in a single shot, which can reduce the experimental uncertainties from shot-to-shot fluctuations. The new crystal spectrometer has been used in the X-ray opacity experiment to precisely measure the aluminum K-absorption edge shift in the energy range around 1.560 keV in strongly compressed matter. It is demonstrated that the spectrometer can be used to realize measurements of new and unpredictable physical interactions of interest, as well as basic and applied high-energy-density science.展开更多
An aberration-free imaging technique was used to design a double-spherically bent crystal spectrometer with high energy and spatial resolutions to ensure that the individual spectral lines are represented as perfectly...An aberration-free imaging technique was used to design a double-spherically bent crystal spectrometer with high energy and spatial resolutions to ensure that the individual spectral lines are represented as perfectly straight lines on the detector.After obtaining the matched parameters of the two crystals via geometry-based optimization,an alignment method was employed to allow the spacing between the crystals and the detector to be coupled with the source.The working principle of this spectrum-measuring scheme was evaluated using a Cu X-ray tube.High-quality spectra with energy resolutions(E/ΔE)of approximately 3577 were obtained for a relatively large source size.展开更多
Although the streaked optical pyrometer(SOP)system has been widely adopted in shock temperature measurements,its reliability has always been of concern.Here,two calibrated Planckian radiators with different color temp...Although the streaked optical pyrometer(SOP)system has been widely adopted in shock temperature measurements,its reliability has always been of concern.Here,two calibrated Planckian radiators with different color temperatures were used to calibrate and verify the SOP system by comparing the two calibration standards using both multi-channel and single-channel methods.A high-color-temperature standard lamp and a multi-channel filter were specifically designed for the measurement system.To verify the reliability of the SOP system,the relative deviation between the measured data and the standard value of less than 5%was calibrated out,which demonstrates the reliability of the SOP system.Furthermore,a method to analyze the uncertainty and sensitivity of the SOP system is proposed.A series of laserinduced shock experiments were conducted at the‘Shenguang-Ⅱ’laser facility to verify the reliability of the SOP system for temperature measurements at tens of thousands of kelvin.The measured temperature of the quartz in our experiments agreed fairly well with previous works,which serves as evidence for the reliability of the SOP system.展开更多
Using a linear scaling self-consistent-charge density functional tight binding （SCC-DFTB） and an ab initio Omol method, the bonding characteristics and Young＇s modulus of （10, 0） and （10,10） single-walled carbo...Using a linear scaling self-consistent-charge density functional tight binding （SCC-DFTB） and an ab initio Omol method, the bonding characteristics and Young＇s modulus of （10, 0） and （10,10） single-walled carbon nanotubes are calculated. The structure of a graphene is also calculated. It is found that the C-C and C-H bond length, their distribution characteristics on the tube, and Young^s modulus of the tube by linear scaling SCC-DFTB are identical to those by ab initio, while the computing cost by the linear scaling SCC-DFTB is reduced by more than 30 times as compared with that by the Dmol for the （10,0） and （10,10） tubes. By computing the structure of a graphene it is also found that the linear scaling SCCDFTB is reliable and time-saving.展开更多
Organophosphate esters(OPEs)have become one group of chemicals with emerging concern in the marine environment.In this work,we investigated OPEs in the air and seawater of the South China Sea in summer 2019.The concen...Organophosphate esters(OPEs)have become one group of chemicals with emerging concern in the marine environment.In this work,we investigated OPEs in the air and seawater of the South China Sea in summer 2019.The concentrations of∑_(10)OPEs in the atmosphere ranged from 66 to 550 pg/m^(3),with TCIPP,TNBP,TPhP,and TEP predominating in the air.The total dissolved OPE concentrations(∑_(10)OPEs without TEP)measured in high-volume water samples ranged from 300 to 3600 pg/L,with a mean concentration of 1180±910 pg/L.TEP was measured with liquid−liquid extraction(LLE),and it showed the highest concentration(average 2000±1450 pg/L)among the selected OPEs.Total suspended matter associated OPEs accounted for less than 4.7%of the sum of OPE concentrations in seawater.Fugacity fractions and air−sea exchange fluxes showed that TCEP,TCIPP,TIBP,TEHP,TPhP,and EHDPP were favored to volatilize,TEP dominated the deposition,while TPrP and TNBP varied between volatilization and deposition.Atmospheric particle deposition fluxes ranged from 5 to 71 ng/m^(2)/day with an average of 17±15 ng/m^(2)/day.The input of∑OPEs to the entire South China Sea via atmospheric particle deposition was estimated to be 22±19 tons/year,while the net air−sea exchange fluxes of OPEs were volatilization from seawater to air with an average of 44±33 tons/year.This work suggests that air−sea exchange and atmospheric particle deposition are significant processes interfering with the transport of OPEs in the marine environment.展开更多
基金supported by the National Science Foundation of China under Award Nos.12074353 and 12075227.
文摘The use of broadband laser technology is a novel approach for inhibiting processes related to laser plasma interactions(LPIs).In this study,several preliminary experiments into broadband-laser-driven LPIs are carried out using a newly established hundreds-of-joules broadband second-harmonic-generation laser facility.Through direct comparison with LPI results for a traditional narrowband laser,the actual LPI-suppression effect of the broadband laser is shown.The broadband laser had a clear suppressive effect on both back-stimulated Raman scattering and back-stimulated Brillouin scattering at laser intensities below 1×10^(15) W cm^(−2).An abnormal hot-electron phenomenon is also investigated,using targets of different thicknesses.
基金the financial support from the Key Research and Development Program of Ningxia Hui Autonomous Region of China(2021BEF02008)the National Natural Science Foundation of China(32272330)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Western diet(rich in highly refined sugar and fat)can induce a range of metabolic dysfunctions in animals and humans,including neuroinflammation and cognitive function decline.Neuroinflammation and cognitive impairment,two critical pathological characteristics of Alzheimer’s disease,have been closely associated with microbial alteration via the gut-brain axis.Thus,the present study aimed to investigate the influence of 2-O-β-D-glucopyranosyl-L-ascorbic acid(AA-2βG)isolated from the fruits of Lycium barbarum on preventing the high-fructose diet(HFrD)induced neuroinflammation in mice.It was found that AA-2βG prevented HFr D-induced cognitive deficits.AA-2βG also predominantly enhanced the gut barrier integrity,decreased lipopolysaccharide entry into the circulation,which subsequently countered the activation of glial cells and neuroinflammatory response.These beneficial effects were transmissible by horizontal fecal microbiome transplantation,transferring from AA-2βG fed mice to HFr D fed mice.Additionally,AA-2βG exerted neuroprotective effects involving the enrichment of Lactobacillus and Akkermansia,potentially beneficial intestinal bacteria.The present study provided the evidence that AA-2βG could improve indices of cognition and neuroinflammmation via modulating gut dybiosis and preventing leaky gut.As a potential functional food ingredient,AA-2βG may be applied to attenuate neuroinflammation associated with Western-style diets.
基金This work was supported in part by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDA25010100,XDA25010300,and XDA25030100)the National Natural Science Foundation of China(Grant Nos.U1930107 and 11827807)the Japanese Ministry of Education,Science,Sports,and Culture through Grants-in-Aid,KAKENHI(Grant No.21H04454).
文摘The Zeeman splitting effect is observed in a strong magnetic field generated by a laser-driven coil.The expanding plasma from the coil wire surface is concentrated at the coil center and interacts with the simultaneously generated magnetic field.The Cu I spectral lines at wavelengths of 510.5541,515.3235,and 521.8202 nm are detected and analyzed.The splittings of spectral lines are used to estimate the magnetic field strength at the coil center as∼31.4±15.7 T at a laser intensity of∼5.6310^(15) W/cm^(2),which agrees well with measurements using a B-dot probe.Some other plasma parameters of the central plasma disk are also studied.The temperature is evaluated from the Cu I spectral line intensity ratio,while the electron density is estimated from the Stark broadening effect.
基金the National Natural Science Foundation of China(Nos.22104158,82174104,U1903211)the Natural Science Foundation of Hunan Province(No.2021JJ40041)+1 种基金Guangdong Basic and Applied Basic Research Foundation(No.2023A1515011346)Shenzhen Science and Technology Program(No.SZBH202130)。
文摘Heterodimerization in RTKs is of vital importance in the RTK signaling and cell functions.Heterodimerization between RTKs can result in diversity of downstream signals,increasing the ability of cells to respond to external experiments.Traditional RTKs heterodimerization always occur in the same families and is lack of agonists to activate the heterodimeric RTKs signaling pathway.Herein,we developed the DNA agonist based on bivalent aptamers for the heterodimerized RTKs of different families,AF/AM-1,which could simultaneously activate FGFR1 and c-Met signaling.It is the first agonist that realizing the heterodimerization and activation of FGFR1 and c-Met,two different RTK families.The activation of FGFR1/c-Met heterodimer result in the down-stream signals transduction,such as the phosphorylation of Akt and Erk,inducing the cell migration and proliferation.The DNA agonist for RTK heterodimer of different families would have potential applications in the fields of biomedicine.
基金supported by the National Natural Science Foundation of China(31925019 to P.C.)the STI 2030 Major Projects(2021ZD0202701to P.C.)the New Cornerstone Science Foundation through the XPLORER PRIZE(to P.C.).All data are archived in NIBS.
文摘Cough is a vital defensive reflex for expelling harmful substances from the airway.The sensory afferents for the cough reflex have been intensively studied.However,the brain mechanisms underlying the cough reflex remain poorly understood.Here,we developed a paradigm to quantitatively measure cough-like reflexes in mice.Using this paradigm,we found that prodynorphin-expressing(Pdyn+)neurons in the nucleus of the solitary tract(NTS)are critical for capsaicin-induced cough-like reflexes.These neurons receive cough-related neural signals from Trpv1+vagal sensory neurons.The activation of Pdyn+NTS neurons triggered respiratory responses resembling cough-like reflexes.Among the divergent projections of Pdyn+NTS neurons,a glutamatergic pathway projecting to the caudal ventral respiratory group(cVRG),the canonical cough center,was necessary and sufficient for capsaicin-induced cough-like reflexes.These results reveal that Pdyn+NTS neurons,as a key neuronal population at the entry point of the vagus nerve to the brainstem,initiate cough-like reflexes in mice.
基金supported by the National Natural Science Foundation of China under grant Nos. 50772134 and 50802115the National Basic Research Program of China ("973 Program") under grant No. 2006CB600901
文摘Oxidation protective MoSi2-MosSi3/SiC multi-coatings for carbon/carbon composites were prepared by chemical vapor reaction and slurry-sintering method. The influence of preparation technology on the structure and phase composition of the coating was investigated by scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS） and X-ray diffraction （XRD） analyses, and then their relationship was discussed. The results indicate that the Si/Mo ratio of the slurry and sintering processing were two main factors that significantly affected the structure and phase composition of the multi-coating. Appropriate sintering process and relatively high Si/Mo ratio were essential for preparing the multi-coating with dense structure and favorable phase composition. After being sintered at 1723 K for 2 h and with the Si/Mo ratio of the slurry being 4.5 （weight ratio）, a dense structure accompanied by favorable phase composition of the coating can be obtained. When heat treated at 2373 K for I h, this coating became more compact and continuous. Oxidation tests （performed at 1623 and 1823 K） demonstrated that both of these two obtained multi-coatings exhibited better anti-oxidation property than single layer SiC coating.
基金the German Federal Environmental Foundation for sponsoring the project.
文摘The distribution of polyfluoroalkyl compounds(PFCs)in the dissolved and particulate phase and their discharge from the river Elbe into the North Sea were studied.The PFCs quantified included C_(4)-C_(8) perfluorinated sulfonates(PFSAs),6∶2 fluorotelomer sulfonate(6∶2 FTS),C_(6) and C_(8) perfluorinated sulfinates(PFSiAs),C_(4)-C_(12) perfluorinated carboxylic acids(PFCAs),perfluoro-3,7-dimethyl-octanoic acid(3,7m_(2)-PFOA),perfluorooctane sulfonamide(FOSA),and n-ethyl perfluroctane sulfonamidoethanol(EtFOSE).PFCs were mostly distributed in the dissolved phase,where perfluorooctanoic acid(PFOA)dominated with 2.9–12.5 ng/L.In the suspended particulate matter FOSA and perfluorooctane sulfonate(PFOS)showed the highest concentrations(4.0 ng/L and 2.3 ng/L,respectively).The total flux ofΣPFCs from the river Elbe was estimated to be 802 kg/year for the dissolved phase and 152 kg/year for the particulate phase.This indicates that the river Elbe acts as a source of PFCs into the North Sea.However,the concentrations of perfluorobutane sulfonate(PFBS)and perfluorobutanoic acid(PFBA)in the North Sea were higher than that in the river Elbe,thus an alternative source must exist for these compounds.
基金Additional funding was provided by the Student Grant Competition of CTU(No.SGS22/180/OHK4/3T/14)the Ministry of Education,Youth&Sports of the Czech Republic(No.LM2018114)+1 种基金the Horizon 2020 project Laserlab-Europe V(No.871124)This work was funded by the Helmholtz Association(No.VHNG-1338).
文摘A new approach to target development for laboratory astrophysics experiments at high-power laser facilities is presented.With the dawn of high-power lasers,laboratory astrophysics has emerged as a field,bringing insight into physical processes in astrophysical objects,such as the formation of stars.An important factor for success in these experiments is targetry.To date,targets have mainly relied on expensive and challenging microfabrication methods.The design presented incorporates replaceable machined parts that assemble into a structure that defines the experimental geometry.This can make targets cheaper and faster to manufacture,while maintaining robustness and reproducibility.The platform is intended for experiments on plasma flows,but it is flexible and may be adapted to the constraints of other experimental setups.Examples of targets used in experimental campaigns are shown,including a design for insertion in a high magnetic field coil.Experimental results are included,demonstrating the performance of the targets.
基金supported by the Science and Technology Program of Guangzhou,China (No. 201707010219)the National Natural Science Foundation of China (No. 41877295)the Project of China Geological Survey (No. DD20190627)。
文摘Trace metal(Cr, Ni, Cu, Zn, Cd and Pb) exposures, distribution and bioaccumulation were investigated in marine organisms from Guangdong coastal regions, South China. The results showed that all of the selected metals were observed in marine organisms with a predomination of Cu and Zn. The metal exposure levels exhibited obvious variations between species with the decreasing order of crab > shellfish > shrimp > fish. The higher metals enrichment seen in shellfish and crab species primarily attributed to their living habits and the higher sediment background values of trace metals. Endpoint bioaccumulation factor(BAFfd) was used to characterize the bioaccumulation potentials of marine organisms to trace metals, of which Cu and Zn were the most accumulated elements. The exposure of trace metals in the cultured organisms was far lower than those in wild marine organisms, which is probably due to the effect of growth dilution. Comparisons with previous studies demonstrated that the concentration profiles of most trace metals declined over the last one to two decades, except Cu, that increased indistinctively.
基金the National Basic Research Program(973 Program)(Nos.2006CB500806 and 2009CB941301)。
文摘The mushroom body(MB),a bilateral brain structure pos-sessing about 2000-2500 neurons per hemisphere,plays a central role in olfactory learning and memory in Dros-ophila melanogaster.Extensive studies have demonstrat-ed that three major types of MB neurons(α/β,α’/β’andγ)exhibit distinct functions in memory processing,including the critical role of approximately 1000 MBα/βneurons in retrieving long-term memory.Inspired by recent fi ndings that MBα/βneurons can be further divided into three subdivisions(surface,posterior and core)and wherein theα/βcore neurons play an permissive role in long-term memory consolidation,we examined the functional differ-ences of all the three morphological subdivisions of MBα/βby temporally precise manipulation of their synaptic outputs during long-term memory retrieval.We found the normal neurotransmission from a combination of MBα/βsurface and posterior neurons is necessary for retrieving both aversive and appetitive long-term memory,whereas output from MBα/βposterior or core subdivision alone is dispensable.These results imply a specifi c requirement of about 500 MBα/βneurons in supporting long-term memory retrieval and a further functional partitioning for memory processing within the MBα/βregion.
基金supported by the National Natural Science Foundation of China (Nos. 11575168 and 61475146)the funding through IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
文摘A new crystal spectrometer for application in X-ray opacity experiments is proposed. The conditions necessary to yield broad spectral coverage with a resolution >500, strong rejection of hard X-ray backgrounds and negligible source broadening for extended sources are formulated. In addition, the design, response modeling and reporting of an elliptical crystal spectrometer in conjunction with a linear detector are presented. The measured results demonstrate the performance of the new crystal spectrometer with a broad energy coverage range, high spectral resolution, and high luminosity(good collection efficiency). This spectrometer can be used in combination with point-projection backlighting techniques as utilized in X-ray opacity experiments. Specifically, the X-ray source, transmission and self-emission spectra of the sample can be measured simultaneously in a single shot, which can reduce the experimental uncertainties from shot-to-shot fluctuations. The new crystal spectrometer has been used in the X-ray opacity experiment to precisely measure the aluminum K-absorption edge shift in the energy range around 1.560 keV in strongly compressed matter. It is demonstrated that the spectrometer can be used to realize measurements of new and unpredictable physical interactions of interest, as well as basic and applied high-energy-density science.
基金This work was supported by the National Natural Science Foundation of China(No.11575168).
文摘An aberration-free imaging technique was used to design a double-spherically bent crystal spectrometer with high energy and spatial resolutions to ensure that the individual spectral lines are represented as perfectly straight lines on the detector.After obtaining the matched parameters of the two crystals via geometry-based optimization,an alignment method was employed to allow the spacing between the crystals and the detector to be coupled with the source.The working principle of this spectrum-measuring scheme was evaluated using a Cu X-ray tube.High-quality spectra with energy resolutions(E/ΔE)of approximately 3577 were obtained for a relatively large source size.
基金supported by the National Key R&D Program of China (No. 2017YFA0403200)the Science Challenge Project (No. TZ2016001)
文摘Although the streaked optical pyrometer(SOP)system has been widely adopted in shock temperature measurements,its reliability has always been of concern.Here,two calibrated Planckian radiators with different color temperatures were used to calibrate and verify the SOP system by comparing the two calibration standards using both multi-channel and single-channel methods.A high-color-temperature standard lamp and a multi-channel filter were specifically designed for the measurement system.To verify the reliability of the SOP system,the relative deviation between the measured data and the standard value of less than 5%was calibrated out,which demonstrates the reliability of the SOP system.Furthermore,a method to analyze the uncertainty and sensitivity of the SOP system is proposed.A series of laserinduced shock experiments were conducted at the‘Shenguang-Ⅱ’laser facility to verify the reliability of the SOP system for temperature measurements at tens of thousands of kelvin.The measured temperature of the quartz in our experiments agreed fairly well with previous works,which serves as evidence for the reliability of the SOP system.
基金support by Program for Changjing Schol-ars and Innovative Research Team in University(PSCIRT0720)
文摘Using a linear scaling self-consistent-charge density functional tight binding （SCC-DFTB） and an ab initio Omol method, the bonding characteristics and Young＇s modulus of （10, 0） and （10,10） single-walled carbon nanotubes are calculated. The structure of a graphene is also calculated. It is found that the C-C and C-H bond length, their distribution characteristics on the tube, and Young^s modulus of the tube by linear scaling SCC-DFTB are identical to those by ab initio, while the computing cost by the linear scaling SCC-DFTB is reduced by more than 30 times as compared with that by the Dmol for the （10,0） and （10,10） tubes. By computing the structure of a graphene it is also found that the linear scaling SCCDFTB is reliable and time-saving.
基金supported by the Federal Ministry of Education and Research of Germany(03F0786C and 03G0269)the Hainan Provincial Natural Science Foundation of China(No.422CXTD533)+1 种基金L.M.gratefully acknowledges the China Scholarship Council for financial support.Funding for the cruise was received by J.J.W.(03G0269)the Federal Ministry of Education and Research of Germany.
文摘Organophosphate esters(OPEs)have become one group of chemicals with emerging concern in the marine environment.In this work,we investigated OPEs in the air and seawater of the South China Sea in summer 2019.The concentrations of∑_(10)OPEs in the atmosphere ranged from 66 to 550 pg/m^(3),with TCIPP,TNBP,TPhP,and TEP predominating in the air.The total dissolved OPE concentrations(∑_(10)OPEs without TEP)measured in high-volume water samples ranged from 300 to 3600 pg/L,with a mean concentration of 1180±910 pg/L.TEP was measured with liquid−liquid extraction(LLE),and it showed the highest concentration(average 2000±1450 pg/L)among the selected OPEs.Total suspended matter associated OPEs accounted for less than 4.7%of the sum of OPE concentrations in seawater.Fugacity fractions and air−sea exchange fluxes showed that TCEP,TCIPP,TIBP,TEHP,TPhP,and EHDPP were favored to volatilize,TEP dominated the deposition,while TPrP and TNBP varied between volatilization and deposition.Atmospheric particle deposition fluxes ranged from 5 to 71 ng/m^(2)/day with an average of 17±15 ng/m^(2)/day.The input of∑OPEs to the entire South China Sea via atmospheric particle deposition was estimated to be 22±19 tons/year,while the net air−sea exchange fluxes of OPEs were volatilization from seawater to air with an average of 44±33 tons/year.This work suggests that air−sea exchange and atmospheric particle deposition are significant processes interfering with the transport of OPEs in the marine environment.
