This paper analyses the heteronuclear Cosy Revamped by Asymmetric Z-gradient Echo Detection pulse sequence. General theoretical expressions of the pulse sequence with arbitrary flip angles were derived by using dipola...This paper analyses the heteronuclear Cosy Revamped by Asymmetric Z-gradient Echo Detection pulse sequence. General theoretical expressions of the pulse sequence with arbitrary flip angles were derived by using dipolar field treatment and signals originating from heteronuclear intermolecular single-quantum coherences (iSQCs) in highly-polarized two spin-1/2 systems were mainly discussed in order to find the optimal flip angles. The results show that signals from heteronuclear iSQCs decay slower than those from intermolecular double-quantum coherences or intermolecular zero-quantum coherences. Magical angle experiments validate that the signals are from heteronuclear iSQCs and insensitive to the imperfection of radio-frequency flip angles. All experimental observations are in excellent agreement with theoretical predictions. The quantum-mechanical treatment leads to similar predictions to the dipolar field treatment.展开更多
Coherence, a measure of spectral similarity, may estimate cortical coupling between two EEG signals as a function of frequency. The coherence between EEG signals from different brain areas depends on the structural co...Coherence, a measure of spectral similarity, may estimate cortical coupling between two EEG signals as a function of frequency. The coherence between EEG signals from different brain areas depends on the structural connection and functional coupling between two regions. The theory of hemispheric specialization proposes left hemisphere activation to positive emotions and right one to negative emotions. Other proposal is that right hemisphere activation occurs with emotional stimuli. In the present study EEG coherences were calculated during the presentation of the International Affective Pictures to 36 healthy male university students. The subjects’ task was to determine the valence of the stimuli. Base line recording were done with subjects observing the blank monitor. Our results showed higher coherences during the emotional condition. No differences between negative and positive emotions were obtained. Neutral pictures evoked the highest coherence values. These data suggest that coherences between functionally coupled brain areas do not reflect emotional recognition of the valence of stimuli, but they are internal indicators of different mental processes such as memory, mental effort and arousal. Our findings do not support the theory of hemispheric specialization, neither the theory of right hemisphere;rather they suggest a complex activation pattern that involves mostly frontal areas in connection with the entire cortex.展开更多
A scheme for generating the giant enhancement of the Kerr nonlinearity in a four-level system with the quantum coherences from the decays and the incoherent pumping is proposed. Compared with that generated in a gener...A scheme for generating the giant enhancement of the Kerr nonlinearity in a four-level system with the quantum coherences from the decays and the incoherent pumping is proposed. Compared with that generated in a general four- level system, the Kerr nonlinearity can be enhanced by several orders of magnitude with vanishing linear absorption. By using the numerical results, we show that the remarkable enhancement should be attributed to the interaction of the quantum coherences from the decays and the incoherent pumping.展开更多
Diamond,with ultrahigh hardness,high wear resistance,high thermal conductivity,and so forth,has attracted worldwide attention.However,researchers found emergent reactions at the interfaces between diamond and ferrous ...Diamond,with ultrahigh hardness,high wear resistance,high thermal conductivity,and so forth,has attracted worldwide attention.However,researchers found emergent reactions at the interfaces between diamond and ferrous materials,which significantly affects the performance of diamond-based devices.Herein,combing experiments and theoretical calculations,taking diamond–iron(Fe)interface as a prototype,the counter-diffusion mechanism of Fe/carbon atoms has been established.Surprisingly,it is identified that Fe and diamond first form a coherent interface,and then Fe atoms diffuse into diamond and prefer the carbon vacancies sites.Meanwhile,the relaxed carbon atoms diffuse into the Fe lattice,forming Fe_(3)C.Moreover,graphite is observed at the Fe_(3)C surface when Fe_(3)C is over-saturated by carbon atoms.The present findings are expected to offer new insights into the atomic mechanism for diamondferrous material's interfacial reactions,benefiting diamond-based device applications.展开更多
AIM:To analyze the relationship between optical coherence tomography(OCT)and OCT angiography(OCTA)imaging in patients with diabetic macular edema(DME)who are treated with a combination of aflibercept and triamcinolone...AIM:To analyze the relationship between optical coherence tomography(OCT)and OCT angiography(OCTA)imaging in patients with diabetic macular edema(DME)who are treated with a combination of aflibercept and triamcinolone acetonide(TA).METHODS:A total of 76 eyes newly diagnosed DME were included in this study.They were randomly assigned to receive either aflibercept or a combination of aflibercept and TA.Injections once a month for a total of three injections.Central macular thickness(CMT),number of hyperreflective foci(HRF),height of subretinal fluid(SRF),and area of foveal avascular zone(FAZ)were evaluated using OCT and OCTA at baseline and after each monthly treatment.RESULTS:Both groups showed improvement in best corrected visual acuity(BCVA)and reduction in macular edema after treatment,and the difference in BCVA between the two groups was statistically significant after each treatment(P<0.05).The difference in CMT between the two groups was statistically significant after the first two injections(P<0.01),but not after the third injection(P=0.875).The number of HRF(1mo:7.41±8.25 vs 10.86±7.22,P=0.027;2mo:5.33±6.13 vs 9.12±8.61,P=0.034;3mo:3.58±3.00 vs 6.37±5.97,P=0.007)and height of SRF(1mo:82.39±39.12 vs 105.77±42.26μm,P=0.011;2mo:36.84±10.02 vs 83.59±37.78μm,P<0.01;3mo:11.57±3.29 vs 45.43±12.60μm,P<0.01)in combined group were statistically significant less than aflibercept group after each injection,while the area of FAZ showed no significant change before and after treatment in both groups.CONCLUSION:The combination therapy of aflibercept and TA shows more significant effects on DME eyes with decreased HRF and SRF.However,both aflibercept and combination therapy show no significant change in the area of FAZ.展开更多
We study quantum synchronization under the nonequilibrium reservoirs.We consider a two-qubit XXZ chain coupled independently to their own reservoirs modeled by the collisional model.Two reservoir particles,initially p...We study quantum synchronization under the nonequilibrium reservoirs.We consider a two-qubit XXZ chain coupled independently to their own reservoirs modeled by the collisional model.Two reservoir particles,initially prepared in a thermal state or a state with coherence,are correlated through a unitary transformation and afterward interact locally with the two quantum subsystems.We study the quantum effect of reservoir on synchronous dynamics of system.By preparing different reservoir initial states or manipulating the reservoir particles coupling and the temperature gradient,we find that quantum entanglement of reservoir is the key to control quantum synchronization of system qubits.展开更多
An innovative complex lidar system deployed on an airborne rotorcraft platform for remote sensing of atmospheric pollution is proposed and demonstrated.The system incorporates integrated-path differential absorption l...An innovative complex lidar system deployed on an airborne rotorcraft platform for remote sensing of atmospheric pollution is proposed and demonstrated.The system incorporates integrated-path differential absorption lidar(DIAL) and coherent-doppler lidar(CDL) techniques using a dual tunable TEA CO_(2)laser in the 9—11 μm band and a 1.55 μm fiber laser.By combining the principles of differential absorption detection and pulsed coherent detection,the system enables agile and remote sensing of atmospheric pollution.Extensive static tests validate the system’s real-time detection capabilities,including the measurement of concentration-path-length product(CL),front distance,and path wind speed of air pollution plumes over long distances exceeding 4 km.Flight experiments is conducted with the helicopter.Scanning of the pollutant concentration and the wind field is carried out in an approximately 1 km slant range over scanning angle ranges from 45°to 65°,with a radial resolution of 30 m and10 s.The test results demonstrate the system’s ability to spatially map atmospheric pollution plumes and predict their motion and dispersion patterns,thereby ensuring the protection of public safety.展开更多
The pressure and temperature significantly influence precipitable water vapor(PWV) retrieval. Global Navigation Satellite System(GNSS) PWV retrieval is limited because the GNSS stations lack meteorological sensors. Fi...The pressure and temperature significantly influence precipitable water vapor(PWV) retrieval. Global Navigation Satellite System(GNSS) PWV retrieval is limited because the GNSS stations lack meteorological sensors. First, this article evaluated the accuracy of pressure and temperature in 68 radiosonde stations in China based on ERA5 Reanalysis data from 2015 to 2019 and compared them with GPT3model. Then, the accuracy of pressure and temperature calculated by ERA5 were estimated in 5 representative IGS stations in China. And the PWV calculated by these meteorological parameters from ERA5(ERA5-PWV) were analyzed. Finally, the relation between ERA5-PWV and precipitation was deeply explored using wavelet coherence analysis in IGS stations. These results indicate that the accuracy of pressure and temperature of ERA5 is better than the GPT3 model. In radiosonde stations, the mean BIAS and MAE of pressure and temperature in ERA5 are-0.41/1.15 hpa and-0.97/2.12 K. And the mean RMSEs are 1.35 hpa and 2.87 K, which improve 74.77% and 40.58% compared with GPT3 model. The errors of pressure and temperature of ERA5 are smaller than the GPT3 model in bjfs, hksl and wuh2, and the accuracy of ERA5-PWV is improved by 18.77% compared with the GPT3 model. In addition, there is a significant positive correlation between ERA5-PWV and precipitation. And precipitation is always associated with the sharp rise of ERA5-PWV, which provides important references for rainfall prediction.展开更多
Quantum excitation is usually regarded as a transient process occurring instantaneously,leaving the underlying physics shrouded in mystery.Recent research shows that Rydberg-state excitation with ultrashort laser puls...Quantum excitation is usually regarded as a transient process occurring instantaneously,leaving the underlying physics shrouded in mystery.Recent research shows that Rydberg-state excitation with ultrashort laser pulses can be investigated and manipulated with state-of-the-art few-cycle pulses.We theoretically find that the efficiency of Rydberg state excitation can be enhanced with a short laser pulse and modulated by varying the laser intensities.We also uncover new facets of the excitation dynamics,including the launching of an electron wave packet through strong-field ionization,the re-entry of the electron into the atomic potential and the crucial step where the electron makes a U-turn,resulting in twin captures into Rydberg orbitals.By tuning the laser intensity,we show that the excitation of the Rydberg state can be coherently controlled on a sub-optical-cycle timescale.Our work paves the way toward ultrafast control and coherent manipulation of Rydberg states,thus benefiting Rydberg-state-based quantum technology.展开更多
A quantum teleportation network involving multiple users is essential for future quantum internet.So far,controlled quantum teleportation has been demonstrated in a three-user network.However,versatile and controlled ...A quantum teleportation network involving multiple users is essential for future quantum internet.So far,controlled quantum teleportation has been demonstrated in a three-user network.However,versatile and controlled quantum teleportation network involving more users is in demand,which satisfies different combinations of users for practical requirements.Here we propose a highly versatile and controlled teleportation network that can switch among various combinations of different users.We use a single continuous-variable six-partite Greenberger-Horne-Zeilinger(GHZ)state to realize such a task by choosing the different measurement and feedback operations.The controlled teleportation network,which includes one sub-network,two sub-networks and three sub-networks,can be realized for different application of user combinations.Furthermore,the coherent feedback control(CFC)can manipulate and improve the teleportation performance.Our approach is flexible and scalable,and would provide a versatile platform for demonstrations of complex quantum communication and quantum computing protocols.展开更多
Coherent motion of particles in a plasma can imprint itself on radiation.The recent advent of high-power lasers—allowing the nonlinear inverse Compton-scattering regime to be reached—has opened the possibility of lo...Coherent motion of particles in a plasma can imprint itself on radiation.The recent advent of high-power lasers—allowing the nonlinear inverse Compton-scattering regime to be reached—has opened the possibility of looking at collective effects in laser–plasma interactions.Under certain conditions,the collective interaction of many electrons with a laser pulse can generate coherent radiation in the hard x-ray regime.This perspective paper explains the limitations under which such a regime might be attained.展开更多
In this paper, a two-dimensional(2D) DOA estimation algorithm of coherent signals with a separated linear acoustic vector-sensor(AVS) array consisting of two sparse AVS arrays is proposed. Firstly,the partitioned spat...In this paper, a two-dimensional(2D) DOA estimation algorithm of coherent signals with a separated linear acoustic vector-sensor(AVS) array consisting of two sparse AVS arrays is proposed. Firstly,the partitioned spatial smoothing(PSS) technique is used to construct a block covariance matrix, so as to decorrelate the coherency of signals. Then a signal subspace can be obtained by singular value decomposition(SVD) of the covariance matrix. Using the signal subspace, two extended signal subspaces are constructed to compensate aperture loss caused by PSS.The elevation angles can be estimated by estimation of signal parameter via rotational invariance techniques(ESPRIT) algorithm. At last, the estimated elevation angles can be used to estimate automatically paired azimuth angles. Compared with some other ESPRIT algorithms, the proposed algorithm shows higher estimation accuracy, which can be proved through the simulation results.展开更多
The perfect hybrid vector vortex beam(PHVVB)with helical phase wavefront structure has aroused significant concern in recent years,as its beam waist does not expand with the topological charge(TC).In this work,we inve...The perfect hybrid vector vortex beam(PHVVB)with helical phase wavefront structure has aroused significant concern in recent years,as its beam waist does not expand with the topological charge(TC).In this work,we investigate the spatial quantum coherent modulation effect with PHVVB based on the atomic medium,and we observe the absorption characteristic of the PHVVB with different TCs under variant magnetic fields.We find that the transmission spectrum linewidth of PHVVB can be effectively maintained regardless of the TC.Still,the width of transmission peaks increases slightly as the beam size expands in hot atomic vapor.This distinctive quantum coherence phenomenon,demonstrated by the interaction of an atomic medium with a hybrid vector-structured beam,might be anticipated to open up new opportunities for quantum coherence modulation and accurate magnetic field measurement.展开更多
Due to the spatial characteristics of orbital angular momentum,vortex fields can be applied in the fields of quantum storage and quantum information.We study the realization of spatially modulated vortex fields based ...Due to the spatial characteristics of orbital angular momentum,vortex fields can be applied in the fields of quantum storage and quantum information.We study the realization of spatially modulated vortex fields based on four-wave mixing in a four-level atomic system with a diamond structure.The intensity and spiral phase of the vortex field are effectively transferred to the generated four-wave mixing field.By changing the detuning of the probe field,the phase and intensity of the generated vertex four-wave mixing field can be changed.When the probe field takes a large detuning value,the spatial distribution of the intensity and phase of the vertex four-wave mixing field can be effectively tuned by adjusting the Rabi frequency or detuning value of the coupled field.At the same time,we also provide a detailed explanation based on the dispersion relationship,and the results agree well with our simulation results.展开更多
●AIM:To quantify the performance of artificial intelligence(AI)in detecting glaucoma with spectral-domain optical coherence tomography(SD-OCT)images.●METHODS:Electronic databases including PubMed,Embase,Scopus,Scien...●AIM:To quantify the performance of artificial intelligence(AI)in detecting glaucoma with spectral-domain optical coherence tomography(SD-OCT)images.●METHODS:Electronic databases including PubMed,Embase,Scopus,ScienceDirect,ProQuest and Cochrane Library were searched before May 31,2023 which adopted AI for glaucoma detection with SD-OCT images.All pieces of the literature were screened and extracted by two investigators.Meta-analysis,Meta-regression,subgroup,and publication of bias were conducted by Stata16.0.The risk of bias assessment was performed in Revman5.4 using the QUADAS-2 tool.●RESULTS:Twenty studies and 51 models were selected for systematic review and Meta-analysis.The pooled sensitivity and specificity were 0.91(95%CI:0.86–0.94,I2=94.67%),0.90(95%CI:0.87–0.92,I2=89.24%).The pooled positive likelihood ratio(PLR)and negative likelihood ratio(NLR)were 8.79(95%CI:6.93–11.15,I2=89.31%)and 0.11(95%CI:0.07–0.16,I2=95.25%).The pooled diagnostic odds ratio(DOR)and area under curve(AUC)were 83.58(95%CI:47.15–148.15,I2=100%)and 0.95(95%CI:0.93–0.97).There was no threshold effect(Spearman correlation coefficient=0.22,P>0.05).●CONCLUSION:There is a high accuracy for the detection of glaucoma with AI with SD-OCT images.The application of AI-based algorithms allows together with“doctor+artificial intelligence”to improve the diagnosis of glaucoma.展开更多
At present,the measurement of the near wave field of ships mostly relies on shipborne radar.The commonly used shipborne radar is incoherent and cannot obtain information on wave surface velocity.Therefore,the mathemat...At present,the measurement of the near wave field of ships mostly relies on shipborne radar.The commonly used shipborne radar is incoherent and cannot obtain information on wave surface velocity.Therefore,the mathematical model of wave reconstruction is remarkably complex.As a new type of radar,coherent radar can obtain the radial velocity of the wave surface.Most wave surface reconstruction methods that use wave velocity are currently based on velocity potential.The difficulty of these methods lies in determining the initial value of the velocity integral.This paper proposes a wave surface reconstruction method based on an artificial boundary matrix.Numerical simulation data of regular and short-crest waves are used to verify the accuracy of this method.Simultaneously,the reconstruction stability under different wave velocity measurement errors is analyzed.The calculation results show that the proposed method can effectively realize the reconstruction of wave field.展开更多
Mottness is at the heart of the essential physics in a strongly correlated system as many novel quantum phenomena occur in the metallic phase near the Mott metal–insulator transition. We investigate the Mott transiti...Mottness is at the heart of the essential physics in a strongly correlated system as many novel quantum phenomena occur in the metallic phase near the Mott metal–insulator transition. We investigate the Mott transition in a Hubbard model by using the dynamical mean-field theory and introduce the local quantum state fidelity to depict the Mott metal–insulator transition. The local quantum state fidelity provides a convenient approach to determining the critical point of the Mott transition. Additionally, it presents a consistent description of the two distinct forms of the Mott transition points.展开更多
AIM:To observe the therapeutic effect of conbercept on diabetic macular edema(DME)complicated with diabetic nephropathy(DN).METHODS:In this retrospective study,54 patients(54 eyes)that diagnosed as DME from January 20...AIM:To observe the therapeutic effect of conbercept on diabetic macular edema(DME)complicated with diabetic nephropathy(DN).METHODS:In this retrospective study,54 patients(54 eyes)that diagnosed as DME from January 2017 to October 2021 were collected.The patients were divided into two groups:DME patients with DN(25 eyes),and DME patients without DN(29 eyes).General conditions were collected before treatment,laboratory tests include fasting blood glucose,HbA1c,microalbumin/creatinine,serum creatinine.Optical coherence tomography(OCT)was used to check the ellipsoidal zone(EZ)and external limiting membrane(ELM)integrity.Central macular thickness(CMT),best corrected visual acuity(BCVA),and retinal hyperreflective foci(HF)as well as numbers of injections were recorded.RESULTS:There were significant differences between fasting blood glucose,HbA1c,serum creatinine,urinary microalbumin/creatinine,and estimated glomerular filtration rate(eGFR)between the two groups(all P<0.05).EZ and ELM continuity in the DME+DN group was worse than that in the DME group(P<0.05).BCVA(logMAR)in the DME group was significantly better than that in the DME+DN group at the same time points during treatment(all P<0.05).CMT and HF values were significantly higher in the DME+DN group than that in the DME group at the all time points(all P<0.05)and significantly decreased in both groups with time during treatment.At 6mo after treatment,the mean number of injections in the DME+DN and DME group was 4.84±0.94 and 3.79±0.86,respectively.CONCLUSION:Conbercept has a significant effect in short-term treatment of DME patients with or without DN,and can significantly ameliorate BCVA,CMT and the number of HF,treatment efficacy of DME patients without DN is better than that of DME patients with DN.展开更多
AIM:To assess the repeatability,interocular correlation,and agreement of quantitative swept-source optical coherence tomography angiography(OCTA)optic nerve head(ONH)parameters in healthy subjects.METHODS:Thir ty-thre...AIM:To assess the repeatability,interocular correlation,and agreement of quantitative swept-source optical coherence tomography angiography(OCTA)optic nerve head(ONH)parameters in healthy subjects.METHODS:Thir ty-three healthy subjects were enrolled.The ONH of both eyes were imaged four times by a swept-source-OCTA using a 3 mm×3 mm scanning protocol.Images of the radial peripapillary capillary were analyzed by a customized Matlab program,and the vessel density,fractal dimension,and vessel diameter index were measured.The repeatability of the four scans was determined by the intraclass correlation coefficient(ICC).The most well-centered optic disc from the four repeated scans was then selected for the interocular correlation and agreement analysis using the Pearson correlation coefficient,ICC and Bland-Altman plots.RESULTS:All swept-source-OCTA ONH parameters exhibited certain repeatability,with ICC>0.760 and coefficient of variation(CoV)≤7.301%.The obvious interocular correlation was observed for papillary vessel density(ICC=0.857),vessel diameter index(ICC=0.857)and fractal dimension(ICC=0.906),while circumpapillary vessel density exhibited moderate interocular correlation(ICC=0.687).Bland-Altman plots revealed an agreement range of-5.26%to 6.21%for circumpapillary vessel density.CONCLUSION:OCTA ONH parameters demonstrate good repeatability in healthy subjects.The interocular correlations of papillary vessel density,fractal dimension and vessel diameter index are high,but the correlation for circumpapillary vessel density is moderate.展开更多
AIM:To assess diabetic macular edema(DME)progression during the early phases of the COVID-19 pandemic,when severe societal restrictions raised the concern of possible deterioration of health in patients with systemic ...AIM:To assess diabetic macular edema(DME)progression during the early phases of the COVID-19 pandemic,when severe societal restrictions raised the concern of possible deterioration of health in patients with systemic conditions,particularly those requiring frequent office visits.METHODS:This is a multicenter retrospective chart review of 370 patients(724 eyes)with an established diagnosis of DME seen on 3 separate visits between January 2019 and July 2021.Period 1 was January 2019 to February 2020(considered pre-COVID-19),period 2 was March 2020 to December 2020(considered the height of the pandemic;highest level of pandemic-related clinical and societal regulations)and period 3 was January 2021 to July 2021(re-adjustment to the new“pandemic norms”).Main outcome measures included visual acuity,body mass index(BMI),blood pressure(BP),hemoglobin A1c(HbA1c),macular thickness,patient adherence to scheduled ophthalmology visits,and DME treatment(s)received at each visit.To facilitate measurement of macular thickness,each macula was divided into 9 Early Treatment Diabetic Retinopathy Study(ETDRS)-defined macular sectors as measured by OCT imaging.RESULTS:There was no change of BMI,systolic BP,and diastolic BP between any of the time periods.HbA1c showed a very small increase from period 1(7.6%)to period 2(7.8%,P=0.015)and decreased back to 7.6%at period 3(P=0.12).Macular thickness decreased for 100%of macular regions.The central macular thickness decreased across all 3 periods from 329.5 to 316.6μm(P=0.0045).After analysis of multiple variables including HbA1c,BMI,adherence to scheduled appointments,different clinic centers,and treatment interventions,there was no easily identifiable subgroup of patients that experienced the increase in DME.CONCLUSION:DME doesn’t worsen during the COVID-19 pandemic,instead sustaining a very small but statistically significant improvement.While identifying a mechanism behind our findings is beyond the scope of this study,potential explanations may include a delay in retinal changes beyond our study period,an unexpected increase in treatment frequency despite pandemic restrictions,and an unanticipated pandemic-related improvement in some lifestyle factors that may have had a positive impact on DME.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos 20573084 and 10575085)the Nation Science Foundation of Fujian,China(Grant No A0610005)the Program for New Century Excellent Talents in University of Ministry of Education of China
文摘This paper analyses the heteronuclear Cosy Revamped by Asymmetric Z-gradient Echo Detection pulse sequence. General theoretical expressions of the pulse sequence with arbitrary flip angles were derived by using dipolar field treatment and signals originating from heteronuclear intermolecular single-quantum coherences (iSQCs) in highly-polarized two spin-1/2 systems were mainly discussed in order to find the optimal flip angles. The results show that signals from heteronuclear iSQCs decay slower than those from intermolecular double-quantum coherences or intermolecular zero-quantum coherences. Magical angle experiments validate that the signals are from heteronuclear iSQCs and insensitive to the imperfection of radio-frequency flip angles. All experimental observations are in excellent agreement with theoretical predictions. The quantum-mechanical treatment leads to similar predictions to the dipolar field treatment.
文摘Coherence, a measure of spectral similarity, may estimate cortical coupling between two EEG signals as a function of frequency. The coherence between EEG signals from different brain areas depends on the structural connection and functional coupling between two regions. The theory of hemispheric specialization proposes left hemisphere activation to positive emotions and right one to negative emotions. Other proposal is that right hemisphere activation occurs with emotional stimuli. In the present study EEG coherences were calculated during the presentation of the International Affective Pictures to 36 healthy male university students. The subjects’ task was to determine the valence of the stimuli. Base line recording were done with subjects observing the blank monitor. Our results showed higher coherences during the emotional condition. No differences between negative and positive emotions were obtained. Neutral pictures evoked the highest coherence values. These data suggest that coherences between functionally coupled brain areas do not reflect emotional recognition of the valence of stimuli, but they are internal indicators of different mental processes such as memory, mental effort and arousal. Our findings do not support the theory of hemispheric specialization, neither the theory of right hemisphere;rather they suggest a complex activation pattern that involves mostly frontal areas in connection with the entire cortex.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.10904015,61008063,11004030,and 11074036)
文摘A scheme for generating the giant enhancement of the Kerr nonlinearity in a four-level system with the quantum coherences from the decays and the incoherent pumping is proposed. Compared with that generated in a general four- level system, the Kerr nonlinearity can be enhanced by several orders of magnitude with vanishing linear absorption. By using the numerical results, we show that the remarkable enhancement should be attributed to the interaction of the quantum coherences from the decays and the incoherent pumping.
基金supported by the National Natural Science Foundation of China(Grant Nos.12274371,62271450,U21A2070,21805247,12074345)Cross-Disciplinary Innovative Research Group Project of Henan Province(Grant No.232300421004).
文摘Diamond,with ultrahigh hardness,high wear resistance,high thermal conductivity,and so forth,has attracted worldwide attention.However,researchers found emergent reactions at the interfaces between diamond and ferrous materials,which significantly affects the performance of diamond-based devices.Herein,combing experiments and theoretical calculations,taking diamond–iron(Fe)interface as a prototype,the counter-diffusion mechanism of Fe/carbon atoms has been established.Surprisingly,it is identified that Fe and diamond first form a coherent interface,and then Fe atoms diffuse into diamond and prefer the carbon vacancies sites.Meanwhile,the relaxed carbon atoms diffuse into the Fe lattice,forming Fe_(3)C.Moreover,graphite is observed at the Fe_(3)C surface when Fe_(3)C is over-saturated by carbon atoms.The present findings are expected to offer new insights into the atomic mechanism for diamondferrous material's interfacial reactions,benefiting diamond-based device applications.
基金Supported by the Natural Science Foundation of Guangdong Province,China(No.2022A1515010742)Hunan Provincial Natural Science Foundation of China(No.2023JJ70039)Scientific Research Program of Xiangjiang Philanthropy Foundation.
文摘AIM:To analyze the relationship between optical coherence tomography(OCT)and OCT angiography(OCTA)imaging in patients with diabetic macular edema(DME)who are treated with a combination of aflibercept and triamcinolone acetonide(TA).METHODS:A total of 76 eyes newly diagnosed DME were included in this study.They were randomly assigned to receive either aflibercept or a combination of aflibercept and TA.Injections once a month for a total of three injections.Central macular thickness(CMT),number of hyperreflective foci(HRF),height of subretinal fluid(SRF),and area of foveal avascular zone(FAZ)were evaluated using OCT and OCTA at baseline and after each monthly treatment.RESULTS:Both groups showed improvement in best corrected visual acuity(BCVA)and reduction in macular edema after treatment,and the difference in BCVA between the two groups was statistically significant after each treatment(P<0.05).The difference in CMT between the two groups was statistically significant after the first two injections(P<0.01),but not after the third injection(P=0.875).The number of HRF(1mo:7.41±8.25 vs 10.86±7.22,P=0.027;2mo:5.33±6.13 vs 9.12±8.61,P=0.034;3mo:3.58±3.00 vs 6.37±5.97,P=0.007)and height of SRF(1mo:82.39±39.12 vs 105.77±42.26μm,P=0.011;2mo:36.84±10.02 vs 83.59±37.78μm,P<0.01;3mo:11.57±3.29 vs 45.43±12.60μm,P<0.01)in combined group were statistically significant less than aflibercept group after each injection,while the area of FAZ showed no significant change before and after treatment in both groups.CONCLUSION:The combination therapy of aflibercept and TA shows more significant effects on DME eyes with decreased HRF and SRF.However,both aflibercept and combination therapy show no significant change in the area of FAZ.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12147174 and 61835013)the National Key Research and Development Program of China(Grant Nos.2021YFA1400900,2021YFA0718300,and 2021YFA1400243).
文摘We study quantum synchronization under the nonequilibrium reservoirs.We consider a two-qubit XXZ chain coupled independently to their own reservoirs modeled by the collisional model.Two reservoir particles,initially prepared in a thermal state or a state with coherence,are correlated through a unitary transformation and afterward interact locally with the two quantum subsystems.We study the quantum effect of reservoir on synchronous dynamics of system.By preparing different reservoir initial states or manipulating the reservoir particles coupling and the temperature gradient,we find that quantum entanglement of reservoir is the key to control quantum synchronization of system qubits.
文摘An innovative complex lidar system deployed on an airborne rotorcraft platform for remote sensing of atmospheric pollution is proposed and demonstrated.The system incorporates integrated-path differential absorption lidar(DIAL) and coherent-doppler lidar(CDL) techniques using a dual tunable TEA CO_(2)laser in the 9—11 μm band and a 1.55 μm fiber laser.By combining the principles of differential absorption detection and pulsed coherent detection,the system enables agile and remote sensing of atmospheric pollution.Extensive static tests validate the system’s real-time detection capabilities,including the measurement of concentration-path-length product(CL),front distance,and path wind speed of air pollution plumes over long distances exceeding 4 km.Flight experiments is conducted with the helicopter.Scanning of the pollutant concentration and the wind field is carried out in an approximately 1 km slant range over scanning angle ranges from 45°to 65°,with a radial resolution of 30 m and10 s.The test results demonstrate the system’s ability to spatially map atmospheric pollution plumes and predict their motion and dispersion patterns,thereby ensuring the protection of public safety.
基金supported by Open Fund of Key Laboratory of Mine Environmental Monitoring and Improving around Poyang Lake of Ministry of Natural Resources (Grant MEMI-2021-2022-27)funded by the National Natural Science Foundation of China (Grants 41904031,42374040,42061077)+2 种基金the Jiangxi Provincial Natural Science Foundation (Grants 20202BABL213033)the State Key Laboratory of Geodesy and Earth's Dynamics (Grants SKLGED2021-2-2)the Graduate Innovation Foundation of East China University of Technology (Grants YC2022-s604,YC2022-s609)。
文摘The pressure and temperature significantly influence precipitable water vapor(PWV) retrieval. Global Navigation Satellite System(GNSS) PWV retrieval is limited because the GNSS stations lack meteorological sensors. First, this article evaluated the accuracy of pressure and temperature in 68 radiosonde stations in China based on ERA5 Reanalysis data from 2015 to 2019 and compared them with GPT3model. Then, the accuracy of pressure and temperature calculated by ERA5 were estimated in 5 representative IGS stations in China. And the PWV calculated by these meteorological parameters from ERA5(ERA5-PWV) were analyzed. Finally, the relation between ERA5-PWV and precipitation was deeply explored using wavelet coherence analysis in IGS stations. These results indicate that the accuracy of pressure and temperature of ERA5 is better than the GPT3 model. In radiosonde stations, the mean BIAS and MAE of pressure and temperature in ERA5 are-0.41/1.15 hpa and-0.97/2.12 K. And the mean RMSEs are 1.35 hpa and 2.87 K, which improve 74.77% and 40.58% compared with GPT3 model. The errors of pressure and temperature of ERA5 are smaller than the GPT3 model in bjfs, hksl and wuh2, and the accuracy of ERA5-PWV is improved by 18.77% compared with the GPT3 model. In addition, there is a significant positive correlation between ERA5-PWV and precipitation. And precipitation is always associated with the sharp rise of ERA5-PWV, which provides important references for rainfall prediction.
基金supported by the National Key Research and Development Program of China(Grant No.2019YFA0307703)the National Natural Science Foundation of China(Grant Nos.12234020,11874066,12274461,and 11974426)the Science and Technology Innovation Program of Hunan Province(Grant No.2022RC1193).
文摘Quantum excitation is usually regarded as a transient process occurring instantaneously,leaving the underlying physics shrouded in mystery.Recent research shows that Rydberg-state excitation with ultrashort laser pulses can be investigated and manipulated with state-of-the-art few-cycle pulses.We theoretically find that the efficiency of Rydberg state excitation can be enhanced with a short laser pulse and modulated by varying the laser intensities.We also uncover new facets of the excitation dynamics,including the launching of an electron wave packet through strong-field ionization,the re-entry of the electron into the atomic potential and the crucial step where the electron makes a U-turn,resulting in twin captures into Rydberg orbitals.By tuning the laser intensity,we show that the excitation of the Rydberg state can be coherently controlled on a sub-optical-cycle timescale.Our work paves the way toward ultrafast control and coherent manipulation of Rydberg states,thus benefiting Rydberg-state-based quantum technology.
基金Project supported by the Natural Science Foundation of Shanxi Province of China (Grant No. 202203021221214)the National Natural Science Foundation of China (Grant Nos. 62122044, 62135008, 61925503, 11904218, 12004276, 12147215, and 11834010)+4 种基金the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi Province of China (Grant Nos. 2019L0092 and 2020L0029)the Key Project of the National Key Research and Development Program of China (Grant No. 2022YFA1404500)the Program for the Innovative Talents of Higher Education Institutions of Shanxi Province of Chinathe Program for the Outstanding Innovative Teams of Higher Learning Institutions of Shanxithe Fund for Shanxi “1331 Project” Key Subjects Construction
文摘A quantum teleportation network involving multiple users is essential for future quantum internet.So far,controlled quantum teleportation has been demonstrated in a three-user network.However,versatile and controlled quantum teleportation network involving more users is in demand,which satisfies different combinations of users for practical requirements.Here we propose a highly versatile and controlled teleportation network that can switch among various combinations of different users.We use a single continuous-variable six-partite Greenberger-Horne-Zeilinger(GHZ)state to realize such a task by choosing the different measurement and feedback operations.The controlled teleportation network,which includes one sub-network,two sub-networks and three sub-networks,can be realized for different application of user combinations.Furthermore,the coherent feedback control(CFC)can manipulate and improve the teleportation performance.Our approach is flexible and scalable,and would provide a versatile platform for demonstrations of complex quantum communication and quantum computing protocols.
基金supported by the Czech Academy of Sciences(Mobility Plus Project No.CNRS-23-12)A.M.F.was supported by the Russian Science Foundation(Grant No.20-12-00077).
文摘Coherent motion of particles in a plasma can imprint itself on radiation.The recent advent of high-power lasers—allowing the nonlinear inverse Compton-scattering regime to be reached—has opened the possibility of looking at collective effects in laser–plasma interactions.Under certain conditions,the collective interaction of many electrons with a laser pulse can generate coherent radiation in the hard x-ray regime.This perspective paper explains the limitations under which such a regime might be attained.
基金supported by the National Natural Science Foundation of China (62261047,62066040)the Foundation of Top-notch Talents by Education Department of Guizhou Province of China (KY[2018]075)+3 种基金the Science and Technology Foundation of Guizhou Province of China (ZK[2022]557,[2020]1Y004)the Science and Technology Research Program of the Chongqing Municipal Education Commission (KJQN202200637)PhD Research Start-up Foundation of Tongren University (trxyDH1710)Tongren Science and Technology Planning Project ((2018)22)。
文摘In this paper, a two-dimensional(2D) DOA estimation algorithm of coherent signals with a separated linear acoustic vector-sensor(AVS) array consisting of two sparse AVS arrays is proposed. Firstly,the partitioned spatial smoothing(PSS) technique is used to construct a block covariance matrix, so as to decorrelate the coherency of signals. Then a signal subspace can be obtained by singular value decomposition(SVD) of the covariance matrix. Using the signal subspace, two extended signal subspaces are constructed to compensate aperture loss caused by PSS.The elevation angles can be estimated by estimation of signal parameter via rotational invariance techniques(ESPRIT) algorithm. At last, the estimated elevation angles can be used to estimate automatically paired azimuth angles. Compared with some other ESPRIT algorithms, the proposed algorithm shows higher estimation accuracy, which can be proved through the simulation results.
基金Project supported by the Youth Innovation Promotion Association CASState Key Laboratory of Transient Optics and Photonics Open Topics (Grant No. SKLST202222)
文摘The perfect hybrid vector vortex beam(PHVVB)with helical phase wavefront structure has aroused significant concern in recent years,as its beam waist does not expand with the topological charge(TC).In this work,we investigate the spatial quantum coherent modulation effect with PHVVB based on the atomic medium,and we observe the absorption characteristic of the PHVVB with different TCs under variant magnetic fields.We find that the transmission spectrum linewidth of PHVVB can be effectively maintained regardless of the TC.Still,the width of transmission peaks increases slightly as the beam size expands in hot atomic vapor.This distinctive quantum coherence phenomenon,demonstrated by the interaction of an atomic medium with a hybrid vector-structured beam,might be anticipated to open up new opportunities for quantum coherence modulation and accurate magnetic field measurement.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11704151 and 11247201)the Twelfth Five-year Program for Science and Technology of Education Department of Jilin Province (Grant No.20150215)。
文摘Due to the spatial characteristics of orbital angular momentum,vortex fields can be applied in the fields of quantum storage and quantum information.We study the realization of spatially modulated vortex fields based on four-wave mixing in a four-level atomic system with a diamond structure.The intensity and spiral phase of the vortex field are effectively transferred to the generated four-wave mixing field.By changing the detuning of the probe field,the phase and intensity of the generated vertex four-wave mixing field can be changed.When the probe field takes a large detuning value,the spatial distribution of the intensity and phase of the vertex four-wave mixing field can be effectively tuned by adjusting the Rabi frequency or detuning value of the coupled field.At the same time,we also provide a detailed explanation based on the dispersion relationship,and the results agree well with our simulation results.
文摘●AIM:To quantify the performance of artificial intelligence(AI)in detecting glaucoma with spectral-domain optical coherence tomography(SD-OCT)images.●METHODS:Electronic databases including PubMed,Embase,Scopus,ScienceDirect,ProQuest and Cochrane Library were searched before May 31,2023 which adopted AI for glaucoma detection with SD-OCT images.All pieces of the literature were screened and extracted by two investigators.Meta-analysis,Meta-regression,subgroup,and publication of bias were conducted by Stata16.0.The risk of bias assessment was performed in Revman5.4 using the QUADAS-2 tool.●RESULTS:Twenty studies and 51 models were selected for systematic review and Meta-analysis.The pooled sensitivity and specificity were 0.91(95%CI:0.86–0.94,I2=94.67%),0.90(95%CI:0.87–0.92,I2=89.24%).The pooled positive likelihood ratio(PLR)and negative likelihood ratio(NLR)were 8.79(95%CI:6.93–11.15,I2=89.31%)and 0.11(95%CI:0.07–0.16,I2=95.25%).The pooled diagnostic odds ratio(DOR)and area under curve(AUC)were 83.58(95%CI:47.15–148.15,I2=100%)and 0.95(95%CI:0.93–0.97).There was no threshold effect(Spearman correlation coefficient=0.22,P>0.05).●CONCLUSION:There is a high accuracy for the detection of glaucoma with AI with SD-OCT images.The application of AI-based algorithms allows together with“doctor+artificial intelligence”to improve the diagnosis of glaucoma.
基金Supported by the National Natural Science Foundation of China under Grant No.51809066.
文摘At present,the measurement of the near wave field of ships mostly relies on shipborne radar.The commonly used shipborne radar is incoherent and cannot obtain information on wave surface velocity.Therefore,the mathematical model of wave reconstruction is remarkably complex.As a new type of radar,coherent radar can obtain the radial velocity of the wave surface.Most wave surface reconstruction methods that use wave velocity are currently based on velocity potential.The difficulty of these methods lies in determining the initial value of the velocity integral.This paper proposes a wave surface reconstruction method based on an artificial boundary matrix.Numerical simulation data of regular and short-crest waves are used to verify the accuracy of this method.Simultaneously,the reconstruction stability under different wave velocity measurement errors is analyzed.The calculation results show that the proposed method can effectively realize the reconstruction of wave field.
基金Project supported by the Scientific Research Foundation for Youth Academic Talent of Inner Mongolia University (Grant No.1000023112101/010)the Fundamental Research Funds for the Central Universities of China (Grant No.JN200208)+2 种基金supported by the National Natural Science Foundation of China (Grant No.11474023)supported by the National Key Research and Development Program of China (Grant No.2021YFA1401803)the National Natural Science Foundation of China (Grant Nos.11974051 and 11734002)。
文摘Mottness is at the heart of the essential physics in a strongly correlated system as many novel quantum phenomena occur in the metallic phase near the Mott metal–insulator transition. We investigate the Mott transition in a Hubbard model by using the dynamical mean-field theory and introduce the local quantum state fidelity to depict the Mott metal–insulator transition. The local quantum state fidelity provides a convenient approach to determining the critical point of the Mott transition. Additionally, it presents a consistent description of the two distinct forms of the Mott transition points.
文摘AIM:To observe the therapeutic effect of conbercept on diabetic macular edema(DME)complicated with diabetic nephropathy(DN).METHODS:In this retrospective study,54 patients(54 eyes)that diagnosed as DME from January 2017 to October 2021 were collected.The patients were divided into two groups:DME patients with DN(25 eyes),and DME patients without DN(29 eyes).General conditions were collected before treatment,laboratory tests include fasting blood glucose,HbA1c,microalbumin/creatinine,serum creatinine.Optical coherence tomography(OCT)was used to check the ellipsoidal zone(EZ)and external limiting membrane(ELM)integrity.Central macular thickness(CMT),best corrected visual acuity(BCVA),and retinal hyperreflective foci(HF)as well as numbers of injections were recorded.RESULTS:There were significant differences between fasting blood glucose,HbA1c,serum creatinine,urinary microalbumin/creatinine,and estimated glomerular filtration rate(eGFR)between the two groups(all P<0.05).EZ and ELM continuity in the DME+DN group was worse than that in the DME group(P<0.05).BCVA(logMAR)in the DME group was significantly better than that in the DME+DN group at the same time points during treatment(all P<0.05).CMT and HF values were significantly higher in the DME+DN group than that in the DME group at the all time points(all P<0.05)and significantly decreased in both groups with time during treatment.At 6mo after treatment,the mean number of injections in the DME+DN and DME group was 4.84±0.94 and 3.79±0.86,respectively.CONCLUSION:Conbercept has a significant effect in short-term treatment of DME patients with or without DN,and can significantly ameliorate BCVA,CMT and the number of HF,treatment efficacy of DME patients without DN is better than that of DME patients with DN.
基金Natural Science Foundation of Guangdong Province(No.2018A0303130306)Shantou Science and Technology Program(No.190917085269835,No.200629165261641).
文摘AIM:To assess the repeatability,interocular correlation,and agreement of quantitative swept-source optical coherence tomography angiography(OCTA)optic nerve head(ONH)parameters in healthy subjects.METHODS:Thir ty-three healthy subjects were enrolled.The ONH of both eyes were imaged four times by a swept-source-OCTA using a 3 mm×3 mm scanning protocol.Images of the radial peripapillary capillary were analyzed by a customized Matlab program,and the vessel density,fractal dimension,and vessel diameter index were measured.The repeatability of the four scans was determined by the intraclass correlation coefficient(ICC).The most well-centered optic disc from the four repeated scans was then selected for the interocular correlation and agreement analysis using the Pearson correlation coefficient,ICC and Bland-Altman plots.RESULTS:All swept-source-OCTA ONH parameters exhibited certain repeatability,with ICC>0.760 and coefficient of variation(CoV)≤7.301%.The obvious interocular correlation was observed for papillary vessel density(ICC=0.857),vessel diameter index(ICC=0.857)and fractal dimension(ICC=0.906),while circumpapillary vessel density exhibited moderate interocular correlation(ICC=0.687).Bland-Altman plots revealed an agreement range of-5.26%to 6.21%for circumpapillary vessel density.CONCLUSION:OCTA ONH parameters demonstrate good repeatability in healthy subjects.The interocular correlations of papillary vessel density,fractal dimension and vessel diameter index are high,but the correlation for circumpapillary vessel density is moderate.
文摘AIM:To assess diabetic macular edema(DME)progression during the early phases of the COVID-19 pandemic,when severe societal restrictions raised the concern of possible deterioration of health in patients with systemic conditions,particularly those requiring frequent office visits.METHODS:This is a multicenter retrospective chart review of 370 patients(724 eyes)with an established diagnosis of DME seen on 3 separate visits between January 2019 and July 2021.Period 1 was January 2019 to February 2020(considered pre-COVID-19),period 2 was March 2020 to December 2020(considered the height of the pandemic;highest level of pandemic-related clinical and societal regulations)and period 3 was January 2021 to July 2021(re-adjustment to the new“pandemic norms”).Main outcome measures included visual acuity,body mass index(BMI),blood pressure(BP),hemoglobin A1c(HbA1c),macular thickness,patient adherence to scheduled ophthalmology visits,and DME treatment(s)received at each visit.To facilitate measurement of macular thickness,each macula was divided into 9 Early Treatment Diabetic Retinopathy Study(ETDRS)-defined macular sectors as measured by OCT imaging.RESULTS:There was no change of BMI,systolic BP,and diastolic BP between any of the time periods.HbA1c showed a very small increase from period 1(7.6%)to period 2(7.8%,P=0.015)and decreased back to 7.6%at period 3(P=0.12).Macular thickness decreased for 100%of macular regions.The central macular thickness decreased across all 3 periods from 329.5 to 316.6μm(P=0.0045).After analysis of multiple variables including HbA1c,BMI,adherence to scheduled appointments,different clinic centers,and treatment interventions,there was no easily identifiable subgroup of patients that experienced the increase in DME.CONCLUSION:DME doesn’t worsen during the COVID-19 pandemic,instead sustaining a very small but statistically significant improvement.While identifying a mechanism behind our findings is beyond the scope of this study,potential explanations may include a delay in retinal changes beyond our study period,an unexpected increase in treatment frequency despite pandemic restrictions,and an unanticipated pandemic-related improvement in some lifestyle factors that may have had a positive impact on DME.