We propose an all-optical,single-laser-pulse scheme for generating a dense relativistic strongly magnetized electron-positron pair plasma.The scheme involves the interaction of an extremely intense(I■10^(24) W/cm^(2)...We propose an all-optical,single-laser-pulse scheme for generating a dense relativistic strongly magnetized electron-positron pair plasma.The scheme involves the interaction of an extremely intense(I■10^(24) W/cm^(2))circularly polarized laser pulse with a solid-density target containing a conical cavity.Through full-scale three-dimensional particle-in-cell simulations that account for quantum electrodynamic effects,it is shown that this interaction results in two significant outcomes:first,the generation of quasi-static magnetic fields reaching tens of gigagauss,and,second,the production of large quantities of electron-positron pairs(up to 10^(13))via the Breit-Wheeler process.The e^(-)e^(+)plasma becomes trapped in the magnetic field and remains confined in a small volume for hundreds of femtoseconds,far exceeding the laser timescale.The dependence of pair plasma parameters,as well as the efficiency of plasma production and confinement,is discussed in relation to the properties of the laser pulse and the target.Realizing this scheme experimentally would enable the investigation of physical processes relevant to extreme astrophysical environments.展开更多
In a recent paper published in Phys.Rev.Lett.133,152503(2024),H.Zhang,T.Li,and X.Wang predicted that modern intense lasers can induce highly nonlinear responses in the 229 Th nucleus for the first time,which is an ast...In a recent paper published in Phys.Rev.Lett.133,152503(2024),H.Zhang,T.Li,and X.Wang predicted that modern intense lasers can induce highly nonlinear responses in the 229 Th nucleus for the first time,which is an astonishing effect of light-nucleus interactions.This phenomenon is underpinned by two key factors:(1)the presence of a very low-lying nuclear excited state and(2)a nuclear hyperfine mixing effect that significantly enhances light-nucleus coupling.The resulting highly nonlinear responses facilitate efficient nuclear excitation and enable coherent light emission from the nucleus,resulting in high harmonic generation.229 Th presents a promising platform for advancements in both laser-nuclear physics and nuclear clock development.The pioneering work by Zhang et al.marks a new frontier in light-matter interactions.展开更多
The aim of this study was to evaluate the factors influencing the inactivation effect of intense pulsed light(IPL)on Aeromonas salmonicida grown on chicken meat and skin,and to further develop prediction models of ina...The aim of this study was to evaluate the factors influencing the inactivation effect of intense pulsed light(IPL)on Aeromonas salmonicida grown on chicken meat and skin,and to further develop prediction models of inactivation.In this work,chicken meat and skin inoculated with meat-borne A.salmonicida isolates were subjected to IPL treatments under different conditions.The results showed that IPL had obvious bactericidal effect in the chicken skin and thickness groups when the treatment voltage and time were 7 V combined with 5 s.In addition,the lethality curves of A.salmonicida were fitted under IPL conditions of 3.5-7.5 V.The comparison of statistical parameters revealed that the Weibull model could best fit the mortality curves and could accurately predict the mortality dynamic of A.salmonicida grown on chicken skin.And further a secondary model between the scale factor b and the treatment voltage in Weibull model was established using linear equations,which determined that the secondary model could accurately predict the inactivation of A.salmonicida.This study provides a theoretical basis for future prediction models of Aeromonas,and also provides new ideas for sterilization approaches of meat-borne Aeromonas.展开更多
Slits have been widely used in laser-plasma interactions as plasma optical components for generating high-harmonic light and controlling laser-driven particle beams.Here,we propose and demonstrate that periodic thin s...Slits have been widely used in laser-plasma interactions as plasma optical components for generating high-harmonic light and controlling laser-driven particle beams.Here,we propose and demonstrate that periodic thin slits can be regarded as a new breed of optical elements for efficient focusing and guiding of intense laser pulse.The fundamental physics of intense laser interaction with thin slits is studied,and it is revealed that relativistic effects can lead to enhanced laser focusing far beyond the pure diffractive focusing regime.In addition,the interaction of an intense laser pulse with periodic thin slits makes it feasible to achieve multifold enhancement in both laser intensity and energy transfer efficiency compared with conventional waveguides.These results provide a novel method for manipulating ultra-intense laser pulses and should be of interest for many laser-based applications.展开更多
Background:Physiological and biochemical processes across tissues of the body are regulated in response to the high demands of intense physical activity in several occupations,such as firefighting,law enforcement,mili...Background:Physiological and biochemical processes across tissues of the body are regulated in response to the high demands of intense physical activity in several occupations,such as firefighting,law enforcement,military,and sports.A better understanding of such processes can ultimately help improve human performance and prevent illnesses in the work environment.Methods:To study regulatory processes in intense physical activity simulating real-life conditions,we performed a multi-omics analysis of 3 biofluids(blood plasma,urine,and saliva)collected from 11 wildland firefighters before and after a 45 min,intense exercise regimen.Omics profiles post-vs.pre-exercise were compared by Student’s t-test followed by pathway analysis and comparison between the different omics modalities.Results:Our multi-omics analysis identified and quantified 3835 proteins,730 lipids and 182 metabolites combining the 3 different types of samples.The blood plasma analysis revealed signatures of tissue damage and acute repair response accompanied by enhanced carbon metabolism to meet energy demands.The urine analysis showed a strong,concomitant regulation of 6 out of 8 identified proteins from the renin-angiotensin system supporting increased excretion of catabolites,reabsorption of nutrients and maintenance of fluid balance.In saliva,we observed a decrease in 3 pro-inflammatory cytokines and an increase in 8 antimicrobial peptides.A systematic literature review identified 6 papers that support an altered susceptibility to respiratory infection.Conclusions:This study shows simultaneous regulatory signatures in biofluids indicative of homeostatic maintenance during intense physical activity with possible effects on increased infection susceptibility,suggesting that caution against respiratory diseases could benefit workers on highly physical demanding jobs.展开更多
The Brown-Preston-Singleton(BPS)stopping power model is added to our previously developed hybrid code to model ion beam-plasma interaction.Hybrid simulations show that both resistive field and ion scattering effects a...The Brown-Preston-Singleton(BPS)stopping power model is added to our previously developed hybrid code to model ion beam-plasma interaction.Hybrid simulations show that both resistive field and ion scattering effects are important for proton beam transport in a solid target,in which they compete with each other.When the target is not completely ionized,the self-generated resistive field effect dominates over the ion scattering effect.However,when the target is completely ionized,this situation is reversed.Moreover,it is found that Ohmic heating is important for higher current densities and materials with high resistivity.The energy fraction deposited as Ohmic heating can be as high as 20%-30%.Typical ion divergences with half-angles of about 5°-10°will modify the proton energy deposition substantially and should be taken into account.展开更多
Neutron production driven by intense lasers utilizing inverse kinematic reactions is explored self-consistently by a combination of particle-in-cell simulations for laser-driven ion acceleration and Monte Carlo nuclea...Neutron production driven by intense lasers utilizing inverse kinematic reactions is explored self-consistently by a combination of particle-in-cell simulations for laser-driven ion acceleration and Monte Carlo nuclear reaction simulations for neutron production.It is proposed that laser-driven light-sail acceleration from ultrathin lithium foils can provide an energetic lithium-ion beam as the projectile bombarding a light hydrocarbon target with sufficiently high flux for the inverse p(^(7)Li,n)reaction to be efficiently achieved.Three-dimensional self-consistent simulations show that a forward-directed pulsed neutron source with ultrashort pulse duration 3 ns,small divergence angle 260,and extremely high peak flux 3×10^(14)n/(cm^(2)·s)can be produced by petawatt lasers at intensities of 10^(21)W/cm^(2).These results indicate that a laser-driven neutron source based on inverse kinematics has promise as a novel compact pulsed neutron generator for practical applications,since the it can operate in a safe and repetitive way with almost no undesirable radiation.展开更多
AIM:To investigate the efficacy and mechanisms of indirect intense pulsed light(IPL)irradiation on meibomian gland dysfunction(MGD).METHODS:A total of 60 MGD patients was included in this prospective randomized contro...AIM:To investigate the efficacy and mechanisms of indirect intense pulsed light(IPL)irradiation on meibomian gland dysfunction(MGD).METHODS:A total of 60 MGD patients was included in this prospective randomized controlled trial.Patients were randomly assigned 1:1 into two groups(3-mm group and 10-mm group)in which IPL was applied at distances from the lower eyelid margin of 3 and 10 mm,respectively.Both groups received three times treatment with 3-week interval.Meibomian gland yield secretion score(MGYSS),standard patient evaluation of eye dryness(SPEED)questionnaire,tear break-up time(TBUT),corneal fluorescein staining(CFS),and in vivo confocal microscopy were performed at baseline and after every treatment.RESULTS:After three IPL treatments,both groups had significant improvement in MGYSS(both P<0.05).The noninferiority test showed that improvement in 10-mm group was not inferior to that in 3-mm group(P<0.001).In both groups,temporal regions of both upper and lower eyelids showed significant improvement in MGYSS.Scores of SPEED questionnaire in both groups declined significantly(both P<0.001)and changes of SPEED had no difference between two groups(P=0.57).Density of central corneal subepithelial nerves and TBUTs showed no statistically significant changes.The 3-mm group had improvement on corneal fluorescein staining(P=0.048)and meibomian gland morphology(acini wall thickness P=0.003,hyperreflective points P=0.024)while the 10-mm group had not.CONCLUSION:The efficacy of IPL indirect irradiation in improving meibomian gland secretion and alleviating dry eye symptoms remains unchanged with increase in treatment distance.IPL may primarily act on the functional improvement of the meibomian glands and corneal nerves.展开更多
High-order harmonic generation(HHG) of Ar atom in an elliptically polarized intense laser field is experimentally investigated in this work.Interestingly,the anomalous ellipticity dependence on the laser ellipticity(...High-order harmonic generation(HHG) of Ar atom in an elliptically polarized intense laser field is experimentally investigated in this work.Interestingly,the anomalous ellipticity dependence on the laser ellipticity(ε) in the lower-order harmonics is observed,specifically in the 13rd-order,which displays a maximal harmonic intensity at ε ≈ 0.1,rather than at ε = 0 as expected.This contradicts the general trend of harmonic yield,which typically decreases with the increase of laser ellipticity.In this study,we attribute this phenomenon to the disruption of the symmetry of the wave function by the Coulomb effect,leading to the generation of a harmonic with high ellipticity.This finding provides valuable insights into the behavior of elliptically polarized harmonics and opens up a potential way for exploring new applications in ultrafast spectroscopy and light–matter interactions.展开更多
A supercontinuum white laser with ultrabroad bandwidth,intense pulse energy,and high spectral flatness can be accomplished via synergic action of third-order nonlinearity(3rd-NL)and second-order nonlinearity.In this w...A supercontinuum white laser with ultrabroad bandwidth,intense pulse energy,and high spectral flatness can be accomplished via synergic action of third-order nonlinearity(3rd-NL)and second-order nonlinearity.In this work,we employ an intense Ti:sapphire femtosecond laser with a pulse duration of 50 fs and pulse energy up to 4 mJ to ignite the supercontinuum white laser.Remarkably,we use water instead of the usual solid materials as the 3rd-NL medium exhibiting both strong self-phase modulation and stimulated Raman scattering effect to create a supercontinuum laser with significantly broadened bandwidth and avoid laser damage and destruction.Then the supercontinuum laser is injected into a water-embedded chirped periodically poled lithium niobate crystal that enables broadband and high-efficiency second-harmonic generation.The output white laser has a 10 dB bandwidth encompassing 413 to 907 nm,more than one octave,and a pulse energy of 0.6 mJ.This methodology would open up an efficient route to creating a long-lived,high-stability,and inexpensive white laser with intense pulse energy,high spectral flatness,and ultrabroad bandwidth for application to various areas of basic science and high technology.展开更多
Compressing all the energy of a laser pulse into a spatiotemporal focal cube edged by the laser center wavelength will realize the highest intensity of an ultra-intense ultrashort laser,which is called theλ^(3) regim...Compressing all the energy of a laser pulse into a spatiotemporal focal cube edged by the laser center wavelength will realize the highest intensity of an ultra-intense ultrashort laser,which is called theλ^(3) regime or theλ^(3) laser.Herein,we introduced a rotational hyperbolic mirror—an important rotational conic section mirror with two foci—that is used as a secondary focusing mirror after a rotational parabolic mirror to reduce the focal spot size from several wavelengths to a single wavelength by significantly increasing the focusing angular aperture.Compared with the rotational ellipsoidal mirror,the first focal spot with a high intensity,as well as some unwanted strong-field effects,is avoided.The optimal focusing condition of this method is presented and the enhanced tight focusing for a femtosecond petawatt laser and theλ3 laser is numerically simulated,which can enhance the focused intensities of ultra-intense ultrashort lasers for laser physics.展开更多
Superexcited states of NO molecule and their neutral dissociation processes have been studied both experimentally and theoretically. Neutral excited N^＊ and O^＊ atoms are detected by fluorescence spectroscopy for th...Superexcited states of NO molecule and their neutral dissociation processes have been studied both experimentally and theoretically. Neutral excited N^＊ and O^＊ atoms are detected by fluorescence spectroscopy for the NO molecule upon interaction with 800 nm intense laser radiation of duration 60 fs and intensity 0.2 PW/cm^2. Intense laser pulse causes neutral dissociation of superexcited NO molecule by way of multiphoton excitation, which is equivalent to single photon excitation in the extreme-ultraviolet region by synchrotron radiation. Potential energy curves （PECs） are also built using the calculated superexcited state of NO^＋. In light of the PECs, direct dissociation and pre-dissociation mechanisms are proposed respectively for the neutral dissociation leading to excited fragments N^＊ and O^＊.展开更多
To observe the clinical changes of meibomian gland dysfunctipn(MGD)and ocular Demodex infestation after intense pulsed light(IPL)treatment to further examine the mechanism of IPL treating patients with MGD and ocular ...To observe the clinical changes of meibomian gland dysfunctipn(MGD)and ocular Demodex infestation after intense pulsed light(IPL)treatment to further examine the mechanism of IPL treating patients with MGD and ocular Demodex infestation.The medical records of 25 patients(49 eyes)with MGD treated with IPL,were retrospectively examined to determine outcomes.Associated ocular-surface parameters(ocular surface disease index,OSD1;lipid layer thickness,LLT;noninvasive first breakup time,NIF-BUT;noninvasive average breakup time,NIAvg?BUT;tear film breakup area,TBUA;Schirmer I Test,SIT;corneal fluorescein staining,CFS),eyelid margin abnormalities,meibum quality and expressibility,MG morphological parameters(macrostructure and microstructure),and the number of Demodex infestation were examined before and after treatment.The MG microstructure and the Demodex infestation were examined via in vivo confocal microscopy(IVCM).The results showed that there were statistically significant differences in associated ocular-surface parameters(all P<0.05)before and after IPL treatment,except SIT(P=0.065).Eyelid margin abnormalities,meibum quality and expressibility obviously improved in upper and lower eyelid after IPL treatment(all P<0.0001).MG macrostructure(MG dropouts)decreased in upper(P=0.002)and lower eyelid(P=0.001)after IPL treatment.The nine parameters of MG microstructure in upper and lower eyelid all distinctly improved after IPL treatment(all P<0.0001).The mean number of Demodex mites on the upper lid margin(6.59±7.16 to 3.12±3.81/9 eyelashes)and lower lid margin(2.55±2.11 to 1.29±1.53/9 eyelashes)significantly reduced after IPL treatment(all P<0.0001).The Demodex eradication rate was 20%(8/40)in upper lid margin and 34.15%(14/41)in lower lid margin.These findings indicate that IPL shows great therapeutic potential for patients of MGD and ocular Demodex infestation.展开更多
AIM: To compare the anti-inflammatory effects of intense pulsed light(IPL) with tobramycin/dexamethasone plus warm compress through clinical signs and cytokines in tears.METHODS: Eighty-two patients with dry eye disea...AIM: To compare the anti-inflammatory effects of intense pulsed light(IPL) with tobramycin/dexamethasone plus warm compress through clinical signs and cytokines in tears.METHODS: Eighty-two patients with dry eye disease(DED) associated meibomian gland dysfunction(MGD) were divided into two groups. Group A was treated with IPL, and Group B was treated with tobramycin/dexamethasone plus warm compress. Ocular Surface Disease Index(OSDI), tear film breakup time(TBUT), corneal fluorescein staining(CFS), meibomian gland expressibility(MGE), meibum quality, gland dropout and tear cytokine levels were evaluated before treatment, 1 wk and 1 mo after treatment. RESULTS: TBUT in Group A was higher(P=0.035), and MGE score was lower than Group B at 1 mo(P=0.001). The changes of interleukin(IL)-17 A and IL-1β levels in tears were lower in Group A compared with that in Group B at 1 wk after treatment(P=0.05, P=0.005).CONCLUSION: Treatment with IPL can improve TBUT and MGE and downregulate levels of IL-17 A and IL-1β in tears of patients with DED associated MGD better than treatment with tobramycin/dexamethasone plus warm compress in one-month treatment period.展开更多
Using Joint Warning Typhoon Center （JTWC） best track data during the period 1948-2010, decadal and interdecadal changes of annual category 4 and 5 tropical cyclone （TC） frequency in the western North Pacific basin...Using Joint Warning Typhoon Center （JTWC） best track data during the period 1948-2010, decadal and interdecadal changes of annual category 4 and 5 tropical cyclone （TC） frequency in the western North Pacific basin were examined. By allowing all of the observed TCs in the JTWC dataset to move along the observed TC tracks in a TC intensity model, the annual category 4 and 5 TC frequency was simulated. The results agreed well with observations when the TC intensity prior to 1973 was adjusted based on time-dependent biases due to changes in measurement and reporting practices. The simulated and adjusted time series showed significant decadal （12-18 years） variability, while the interdecadal （18-32 years） variability was found to be statistically insignificant. Numerical simulations indicated that changes in TC tracks are the most important factor for the decadal variability in the category 4 and 5 TC frequency in the western North Pacific basin, while a combined effect of changes in SST and vertical wind shear also contributes to the decadal variability. Further analysis suggested that the active phase of category 4 and 5 TCs is closely associated with an eastward shift in the TC formation locations, which allows more TCs to follow a longer journey, favoring the development of category 4 and 5 TCs. The active phase corresponds with the SST warming over the tropical central and eastern Pacific and the eastward extension of the monsoon trough, thus leading to the eastward shift in TC formation locations.展开更多
Homogeneous mixtures of CH4/air under moderate or intense low-oxygen dilution（MILD） combustion conditions were numerically studied to clarify the fundamental effects of exhaust gas recirculation（EGR）,espe-cially C...Homogeneous mixtures of CH4/air under moderate or intense low-oxygen dilution（MILD） combustion conditions were numerically studied to clarify the fundamental effects of exhaust gas recirculation（EGR）,espe-cially CO2 in EGR gases,on ignition characteristics.Specifically,effects of CO2 addition on autoignition delay time were emphasized at temperature between 1200 K and 1600 K for a wide range of the lean-to-rich equivalence ratio（0.2~2）.The results showed that the ignition delay time increased with equivalence ratio or CO2 dilution ratio.Fur-thermore,ignition delay time was seen to be exponentially related with the reciprocal of initial temperature.Special concern was given to the chemical effects of CO2 on the ignition delay time.The enhancement of ignition delay time with CO2 addition can be mainly ascribed to the decrease of H,O and OH radicals.The predictions of tem-perature profiles and mole fractions of CO and CO2 were strongly related to the chemical effects of CO2.A single ignition time correlation was obtained in form of Arrhenius-type for the entire range of conditions as a function of temperature,CH4 mole fraction and O2 mole fraction.This correlation could successfully capture the complex be-haviors of ignition of CH4/air/CO2 mixture.The results can be applied to MILD combustion as ＂reference time＂,for example,to predict ignition delay time in turbulent reacting flow.展开更多
Employing the two-state model and the time-dependent wave packet method, we have investigated the influences of the parameters of the intense femtosecond laser field on the evolution of the wave packet, as well as the...Employing the two-state model and the time-dependent wave packet method, we have investigated the influences of the parameters of the intense femtosecond laser field on the evolution of the wave packet, as well as the population of ground and double-minimum electronic states of the NaRb molecule. For the different laser wavelengths, the evolution of the wave packet of 6{ }^1／Sigma ^ ＋ state with time and internuclear distance is different, and the different laser intensity brings different influences on the population of the electronic states of the NaRb molecule. One can control the evolutions of wave packet and the population in each state by varying the laser parameters appropriately, which will be a benefit for the light manipulation of atomic and molecular processes.展开更多
A new moving or dynamic thermal tensioning technique-welding with trailing intense cooling was numerically simulated by finite element method(FEM)and experimentally investigated.The simulation results indicate that tr...A new moving or dynamic thermal tensioning technique-welding with trailing intense cooling was numerically simulated by finite element method(FEM)and experimentally investigated.The simulation results indicate that trailing intense cooling can increase significantly the longitudinal tensile plastic strain within the weld and its adjacent zone during cooling stage,which can partially or completely counterbalance the longitudinal compressive plastic strain formed in the heating stage and the solidification shrinkage formed in the cooling stage.Therefore the longitudinal shrinkage remaining in the weld and the adjacent zone is greatly reduced,which means that the residual stresses in the weldments are kept in a lower value and the residual distortion can be mitigated effectively.Meanwhile a series of parametric studies were conducted to demonstrate the influences of several key parameters such as cooling distance, cooling power and cooling width on the effectiveness of distortion control.Experimental results also verify the effectiveness of this distortion control technique and the reliability of the numerical simulation.展开更多
^(62,64)Cu are radioisotopes of medical interest that can be used for positron emission tomography(PET)imaging.Moreover,64Cu hasβ−decay characteristics that allowfor targeted radiotherapy of cancer.In the present wor...^(62,64)Cu are radioisotopes of medical interest that can be used for positron emission tomography(PET)imaging.Moreover,64Cu hasβ−decay characteristics that allowfor targeted radiotherapy of cancer.In the present work,a novel approach to experimentally demonstrate the production of ^(62,64)Cu isotopes fromphotonuclear reactions is proposed in which large-current laser-based electron(e−)beams are generated fromthe interaction between sub-petawatt laser pulses and near-critical-density plasmas.According to simulations,at a laser intensity of 3.431021 W/cm2,a dense e−beamwith a total charge of 100 nCcan be produced,and this in turn produces bremsstrahlung radiation of the order of 1010 photons per laser shot,in the region of the giant dipole resonance.The bremsstrahlung radiation is guided to a natural Cu target,triggering photonuclear reactions to produce themedical isotopes ^(62,64)Cu.An optimal target geometry is employed to maximize the photoneutron yield,and ^(62,64)Cuwith appropriate activities of 0.18 GBq and 0.06 GBq are obtained for irradiation times equal to their respective half-livesmultiplied by three.The detection of the characteristic energy for the nuclear transitions of ^(62,64)Cu is also studied.The results of our calculations support the prospect of producing PET isotopes with gigabecquerel-level activity(equivalent to the required patient dose)using upcoming high-intensity laser facilities.展开更多
High-energy electron radiography(HEER)is a promising diagnostic tool for high-energy-density physics,as an alternative to tools such as X/γ-ray shadowgraphy and high-energy proton radiography.Impressive progress has ...High-energy electron radiography(HEER)is a promising diagnostic tool for high-energy-density physics,as an alternative to tools such as X/γ-ray shadowgraphy and high-energy proton radiography.Impressive progress has been made in the development and application ofHEER in the past fewyears,and its potential for high-resolution imaging of static opaque objects has been proved.In this study,by taking advantage of the short pulse duration and tunable time structure of high-energy electron probes,time-resolved imaging measurements of high-energy-density gold irradiated by ultrashort intense laser pulses are performed.Phenomena at different time scales frompicoseconds to microseconds are observed,thus proving the feasibility of this technique for imaging of static and dynamic objects.展开更多
基金supported by BMBF-Project No.05P24PF1DFG Project No.PU 213/6-3.
文摘We propose an all-optical,single-laser-pulse scheme for generating a dense relativistic strongly magnetized electron-positron pair plasma.The scheme involves the interaction of an extremely intense(I■10^(24) W/cm^(2))circularly polarized laser pulse with a solid-density target containing a conical cavity.Through full-scale three-dimensional particle-in-cell simulations that account for quantum electrodynamic effects,it is shown that this interaction results in two significant outcomes:first,the generation of quasi-static magnetic fields reaching tens of gigagauss,and,second,the production of large quantities of electron-positron pairs(up to 10^(13))via the Breit-Wheeler process.The e^(-)e^(+)plasma becomes trapped in the magnetic field and remains confined in a small volume for hundreds of femtoseconds,far exceeding the laser timescale.The dependence of pair plasma parameters,as well as the efficiency of plasma production and confinement,is discussed in relation to the properties of the laser pulse and the target.Realizing this scheme experimentally would enable the investigation of physical processes relevant to extreme astrophysical environments.
文摘In a recent paper published in Phys.Rev.Lett.133,152503(2024),H.Zhang,T.Li,and X.Wang predicted that modern intense lasers can induce highly nonlinear responses in the 229 Th nucleus for the first time,which is an astonishing effect of light-nucleus interactions.This phenomenon is underpinned by two key factors:(1)the presence of a very low-lying nuclear excited state and(2)a nuclear hyperfine mixing effect that significantly enhances light-nucleus coupling.The resulting highly nonlinear responses facilitate efficient nuclear excitation and enable coherent light emission from the nucleus,resulting in high harmonic generation.229 Th presents a promising platform for advancements in both laser-nuclear physics and nuclear clock development.The pioneering work by Zhang et al.marks a new frontier in light-matter interactions.
基金supported by projects funded by grants from the Natural Science Foundation of Jiangsu Province in China(BK20221515)the National Natural Science Foundation of China(32172266)the Changzhou Science and Technology Support Program(CE20222002)。
文摘The aim of this study was to evaluate the factors influencing the inactivation effect of intense pulsed light(IPL)on Aeromonas salmonicida grown on chicken meat and skin,and to further develop prediction models of inactivation.In this work,chicken meat and skin inoculated with meat-borne A.salmonicida isolates were subjected to IPL treatments under different conditions.The results showed that IPL had obvious bactericidal effect in the chicken skin and thickness groups when the treatment voltage and time were 7 V combined with 5 s.In addition,the lethality curves of A.salmonicida were fitted under IPL conditions of 3.5-7.5 V.The comparison of statistical parameters revealed that the Weibull model could best fit the mortality curves and could accurately predict the mortality dynamic of A.salmonicida grown on chicken skin.And further a secondary model between the scale factor b and the treatment voltage in Weibull model was established using linear equations,which determined that the secondary model could accurately predict the inactivation of A.salmonicida.This study provides a theoretical basis for future prediction models of Aeromonas,and also provides new ideas for sterilization approaches of meat-borne Aeromonas.
基金supported by the National Key R&D Program of China(Grant No.2022YFA1603300)the National Natural Science Foundation of China(Grant Nos.12175154,12205201,12005149,and 11975214)+1 种基金the Shenzhen Science and Technology Program(Grant No.RCYX20221008092851073)used under UK EPSRC Contract Nos.EP/G055165/1 and EP/G056803/1.
文摘Slits have been widely used in laser-plasma interactions as plasma optical components for generating high-harmonic light and controlling laser-driven particle beams.Here,we propose and demonstrate that periodic thin slits can be regarded as a new breed of optical elements for efficient focusing and guiding of intense laser pulse.The fundamental physics of intense laser interaction with thin slits is studied,and it is revealed that relativistic effects can lead to enhanced laser focusing far beyond the pure diffractive focusing regime.In addition,the interaction of an intense laser pulse with periodic thin slits makes it feasible to achieve multifold enhancement in both laser intensity and energy transfer efficiency compared with conventional waveguides.These results provide a novel method for manipulating ultra-intense laser pulses and should be of interest for many laser-based applications.
基金supported by the BRAVE Agile Investment from the PNNL
文摘Background:Physiological and biochemical processes across tissues of the body are regulated in response to the high demands of intense physical activity in several occupations,such as firefighting,law enforcement,military,and sports.A better understanding of such processes can ultimately help improve human performance and prevent illnesses in the work environment.Methods:To study regulatory processes in intense physical activity simulating real-life conditions,we performed a multi-omics analysis of 3 biofluids(blood plasma,urine,and saliva)collected from 11 wildland firefighters before and after a 45 min,intense exercise regimen.Omics profiles post-vs.pre-exercise were compared by Student’s t-test followed by pathway analysis and comparison between the different omics modalities.Results:Our multi-omics analysis identified and quantified 3835 proteins,730 lipids and 182 metabolites combining the 3 different types of samples.The blood plasma analysis revealed signatures of tissue damage and acute repair response accompanied by enhanced carbon metabolism to meet energy demands.The urine analysis showed a strong,concomitant regulation of 6 out of 8 identified proteins from the renin-angiotensin system supporting increased excretion of catabolites,reabsorption of nutrients and maintenance of fluid balance.In saliva,we observed a decrease in 3 pro-inflammatory cytokines and an increase in 8 antimicrobial peptides.A systematic literature review identified 6 papers that support an altered susceptibility to respiratory infection.Conclusions:This study shows simultaneous regulatory signatures in biofluids indicative of homeostatic maintenance during intense physical activity with possible effects on increased infection susceptibility,suggesting that caution against respiratory diseases could benefit workers on highly physical demanding jobs.
基金supported by the National Natural Sci-ence Foundation of China(Grant Nos.12005298,12275356,11774430,U2241281,and 12175309)Research Grant No.PID2022-137339OB-C22 of the Spanish Ministry of Education and Research+1 种基金the Natural Science Foundation of Hunan Province(Grant Nos.2021JJ40661 and 2022JJ30656)a research project of the NUDT(Contract No.ZK19-25).
文摘The Brown-Preston-Singleton(BPS)stopping power model is added to our previously developed hybrid code to model ion beam-plasma interaction.Hybrid simulations show that both resistive field and ion scattering effects are important for proton beam transport in a solid target,in which they compete with each other.When the target is not completely ionized,the self-generated resistive field effect dominates over the ion scattering effect.However,when the target is completely ionized,this situation is reversed.Moreover,it is found that Ohmic heating is important for higher current densities and materials with high resistivity.The energy fraction deposited as Ohmic heating can be as high as 20%-30%.Typical ion divergences with half-angles of about 5°-10°will modify the proton energy deposition substantially and should be taken into account.
基金supported by the National Key R&D Program of China(Grant Nos.2022YFA1603200 and 2022YFA1603201)the National Natural Science Foundation of China(Grant Nos.12135001,11825502,and 11921006)+1 种基金the Strategic Priority Research Program of CAS(Grant No.XDA25050900)the National Natural Science Funds for Distinguished Young Scholars(Grant No.11825502)。
文摘Neutron production driven by intense lasers utilizing inverse kinematic reactions is explored self-consistently by a combination of particle-in-cell simulations for laser-driven ion acceleration and Monte Carlo nuclear reaction simulations for neutron production.It is proposed that laser-driven light-sail acceleration from ultrathin lithium foils can provide an energetic lithium-ion beam as the projectile bombarding a light hydrocarbon target with sufficiently high flux for the inverse p(^(7)Li,n)reaction to be efficiently achieved.Three-dimensional self-consistent simulations show that a forward-directed pulsed neutron source with ultrashort pulse duration 3 ns,small divergence angle 260,and extremely high peak flux 3×10^(14)n/(cm^(2)·s)can be produced by petawatt lasers at intensities of 10^(21)W/cm^(2).These results indicate that a laser-driven neutron source based on inverse kinematics has promise as a novel compact pulsed neutron generator for practical applications,since the it can operate in a safe and repetitive way with almost no undesirable radiation.
基金Supported by the National Natural Science Foundation of China(No.81870629).
文摘AIM:To investigate the efficacy and mechanisms of indirect intense pulsed light(IPL)irradiation on meibomian gland dysfunction(MGD).METHODS:A total of 60 MGD patients was included in this prospective randomized controlled trial.Patients were randomly assigned 1:1 into two groups(3-mm group and 10-mm group)in which IPL was applied at distances from the lower eyelid margin of 3 and 10 mm,respectively.Both groups received three times treatment with 3-week interval.Meibomian gland yield secretion score(MGYSS),standard patient evaluation of eye dryness(SPEED)questionnaire,tear break-up time(TBUT),corneal fluorescein staining(CFS),and in vivo confocal microscopy were performed at baseline and after every treatment.RESULTS:After three IPL treatments,both groups had significant improvement in MGYSS(both P<0.05).The noninferiority test showed that improvement in 10-mm group was not inferior to that in 3-mm group(P<0.001).In both groups,temporal regions of both upper and lower eyelids showed significant improvement in MGYSS.Scores of SPEED questionnaire in both groups declined significantly(both P<0.001)and changes of SPEED had no difference between two groups(P=0.57).Density of central corneal subepithelial nerves and TBUTs showed no statistically significant changes.The 3-mm group had improvement on corneal fluorescein staining(P=0.048)and meibomian gland morphology(acini wall thickness P=0.003,hyperreflective points P=0.024)while the 10-mm group had not.CONCLUSION:The efficacy of IPL indirect irradiation in improving meibomian gland secretion and alleviating dry eye symptoms remains unchanged with increase in treatment distance.IPL may primarily act on the functional improvement of the meibomian glands and corneal nerves.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.92250306,11974137,and 12304302)the National Key Program for Science and Technology Research and Development of China(Grant No.2019YFA0307700)+1 种基金the Natural Science Foundation of Jilin Province,China(Grant Nos.YDZJ202101ZYTS157 and YDZJ202201ZYTS314)the Scientific Research Foundation of the Education Department of Jilin Province,China(Grant No.JJKH20230283KJ)。
文摘High-order harmonic generation(HHG) of Ar atom in an elliptically polarized intense laser field is experimentally investigated in this work.Interestingly,the anomalous ellipticity dependence on the laser ellipticity(ε) in the lower-order harmonics is observed,specifically in the 13rd-order,which displays a maximal harmonic intensity at ε ≈ 0.1,rather than at ε = 0 as expected.This contradicts the general trend of harmonic yield,which typically decreases with the increase of laser ellipticity.In this study,we attribute this phenomenon to the disruption of the symmetry of the wave function by the Coulomb effect,leading to the generation of a harmonic with high ellipticity.This finding provides valuable insights into the behavior of elliptically polarized harmonics and opens up a potential way for exploring new applications in ultrafast spectroscopy and light–matter interactions.
基金supported by the Science and Technology Project of Guangdong (Grant No.2020B010190001)the National Natural Science Foundation of China (Grant No.11974119)+1 种基金the Guangdong Innovative and Entrepreneurial Research Team Program (Grant No.2016ZT06C594)the National Key R&D Program of China (Grant No.2018YFA 0306200).
文摘A supercontinuum white laser with ultrabroad bandwidth,intense pulse energy,and high spectral flatness can be accomplished via synergic action of third-order nonlinearity(3rd-NL)and second-order nonlinearity.In this work,we employ an intense Ti:sapphire femtosecond laser with a pulse duration of 50 fs and pulse energy up to 4 mJ to ignite the supercontinuum white laser.Remarkably,we use water instead of the usual solid materials as the 3rd-NL medium exhibiting both strong self-phase modulation and stimulated Raman scattering effect to create a supercontinuum laser with significantly broadened bandwidth and avoid laser damage and destruction.Then the supercontinuum laser is injected into a water-embedded chirped periodically poled lithium niobate crystal that enables broadband and high-efficiency second-harmonic generation.The output white laser has a 10 dB bandwidth encompassing 413 to 907 nm,more than one octave,and a pulse energy of 0.6 mJ.This methodology would open up an efficient route to creating a long-lived,high-stability,and inexpensive white laser with intense pulse energy,high spectral flatness,and ultrabroad bandwidth for application to various areas of basic science and high technology.
基金supported by the National Key R&D Program of China(Grant No.2022YFA1604401)the Shanghai Science and Technology Committee Program(Grant Nos.22560780100 and 23560750200)the National Natural Science Foundation of China(Grant No.61925507)。
文摘Compressing all the energy of a laser pulse into a spatiotemporal focal cube edged by the laser center wavelength will realize the highest intensity of an ultra-intense ultrashort laser,which is called theλ^(3) regime or theλ^(3) laser.Herein,we introduced a rotational hyperbolic mirror—an important rotational conic section mirror with two foci—that is used as a secondary focusing mirror after a rotational parabolic mirror to reduce the focal spot size from several wavelengths to a single wavelength by significantly increasing the focusing angular aperture.Compared with the rotational ellipsoidal mirror,the first focal spot with a high intensity,as well as some unwanted strong-field effects,is avoided.The optimal focusing condition of this method is presented and the enhanced tight focusing for a femtosecond petawatt laser and theλ3 laser is numerically simulated,which can enhance the focused intensities of ultra-intense ultrashort lasers for laser physics.
文摘Superexcited states of NO molecule and their neutral dissociation processes have been studied both experimentally and theoretically. Neutral excited N^＊ and O^＊ atoms are detected by fluorescence spectroscopy for the NO molecule upon interaction with 800 nm intense laser radiation of duration 60 fs and intensity 0.2 PW/cm^2. Intense laser pulse causes neutral dissociation of superexcited NO molecule by way of multiphoton excitation, which is equivalent to single photon excitation in the extreme-ultraviolet region by synchrotron radiation. Potential energy curves （PECs） are also built using the calculated superexcited state of NO^＋. In light of the PECs, direct dissociation and pre-dissociation mechanisms are proposed respectively for the neutral dissociation leading to excited fragments N^＊ and O^＊.
基金This study was supported by the National Natural Science Foundation of China(No.81670824)the Natural Science Foundation of Hubei Province of China(No.2016CFB421).
文摘To observe the clinical changes of meibomian gland dysfunctipn(MGD)and ocular Demodex infestation after intense pulsed light(IPL)treatment to further examine the mechanism of IPL treating patients with MGD and ocular Demodex infestation.The medical records of 25 patients(49 eyes)with MGD treated with IPL,were retrospectively examined to determine outcomes.Associated ocular-surface parameters(ocular surface disease index,OSD1;lipid layer thickness,LLT;noninvasive first breakup time,NIF-BUT;noninvasive average breakup time,NIAvg?BUT;tear film breakup area,TBUA;Schirmer I Test,SIT;corneal fluorescein staining,CFS),eyelid margin abnormalities,meibum quality and expressibility,MG morphological parameters(macrostructure and microstructure),and the number of Demodex infestation were examined before and after treatment.The MG microstructure and the Demodex infestation were examined via in vivo confocal microscopy(IVCM).The results showed that there were statistically significant differences in associated ocular-surface parameters(all P<0.05)before and after IPL treatment,except SIT(P=0.065).Eyelid margin abnormalities,meibum quality and expressibility obviously improved in upper and lower eyelid after IPL treatment(all P<0.0001).MG macrostructure(MG dropouts)decreased in upper(P=0.002)and lower eyelid(P=0.001)after IPL treatment.The nine parameters of MG microstructure in upper and lower eyelid all distinctly improved after IPL treatment(all P<0.0001).The mean number of Demodex mites on the upper lid margin(6.59±7.16 to 3.12±3.81/9 eyelashes)and lower lid margin(2.55±2.11 to 1.29±1.53/9 eyelashes)significantly reduced after IPL treatment(all P<0.0001).The Demodex eradication rate was 20%(8/40)in upper lid margin and 34.15%(14/41)in lower lid margin.These findings indicate that IPL shows great therapeutic potential for patients of MGD and ocular Demodex infestation.
基金Supported by National Natural Science Foundation of China (No. 81570813)the Lin Hu Scientific Research Foundation of Department of Ophthalmology, Peking University Third Hospital+1 种基金the Scientific Research Foundation for the Excellent Returned Overseas Chinese Scholars, Peking University Third Hospitalthe Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry
文摘AIM: To compare the anti-inflammatory effects of intense pulsed light(IPL) with tobramycin/dexamethasone plus warm compress through clinical signs and cytokines in tears.METHODS: Eighty-two patients with dry eye disease(DED) associated meibomian gland dysfunction(MGD) were divided into two groups. Group A was treated with IPL, and Group B was treated with tobramycin/dexamethasone plus warm compress. Ocular Surface Disease Index(OSDI), tear film breakup time(TBUT), corneal fluorescein staining(CFS), meibomian gland expressibility(MGE), meibum quality, gland dropout and tear cytokine levels were evaluated before treatment, 1 wk and 1 mo after treatment. RESULTS: TBUT in Group A was higher(P=0.035), and MGE score was lower than Group B at 1 mo(P=0.001). The changes of interleukin(IL)-17 A and IL-1β levels in tears were lower in Group A compared with that in Group B at 1 wk after treatment(P=0.05, P=0.005).CONCLUSION: Treatment with IPL can improve TBUT and MGE and downregulate levels of IL-17 A and IL-1β in tears of patients with DED associated MGD better than treatment with tobramycin/dexamethasone plus warm compress in one-month treatment period.
基金jointly supported by the National Natural Science Foundation of China(Grant No.41305050)the Natural Science Foundation of the Jiangsu Higher Education Institutions(Grant No.11KJB170009)+3 种基金the Typhoon Research Project(Grant No.2009CB421503)the Social Commonwealth Research Program of the Ministry of Science and Technology of the People’s Republic of China(Grant No.GYHY200806009)the Key Laboratory of Meteorological Disaster of the Ministry of Education Program(Grant No.KLME1204)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Using Joint Warning Typhoon Center （JTWC） best track data during the period 1948-2010, decadal and interdecadal changes of annual category 4 and 5 tropical cyclone （TC） frequency in the western North Pacific basin were examined. By allowing all of the observed TCs in the JTWC dataset to move along the observed TC tracks in a TC intensity model, the annual category 4 and 5 TC frequency was simulated. The results agreed well with observations when the TC intensity prior to 1973 was adjusted based on time-dependent biases due to changes in measurement and reporting practices. The simulated and adjusted time series showed significant decadal （12-18 years） variability, while the interdecadal （18-32 years） variability was found to be statistically insignificant. Numerical simulations indicated that changes in TC tracks are the most important factor for the decadal variability in the category 4 and 5 TC frequency in the western North Pacific basin, while a combined effect of changes in SST and vertical wind shear also contributes to the decadal variability. Further analysis suggested that the active phase of category 4 and 5 TCs is closely associated with an eastward shift in the TC formation locations, which allows more TCs to follow a longer journey, favoring the development of category 4 and 5 TCs. The active phase corresponds with the SST warming over the tropical central and eastern Pacific and the eastward extension of the monsoon trough, thus leading to the eastward shift in TC formation locations.
基金Supported by the National Natural Science Foundation of China (50206014)the Shuguang Scholar Program of Shanghai Education Development Foundation (05SG23)
文摘Homogeneous mixtures of CH4/air under moderate or intense low-oxygen dilution（MILD） combustion conditions were numerically studied to clarify the fundamental effects of exhaust gas recirculation（EGR）,espe-cially CO2 in EGR gases,on ignition characteristics.Specifically,effects of CO2 addition on autoignition delay time were emphasized at temperature between 1200 K and 1600 K for a wide range of the lean-to-rich equivalence ratio（0.2~2）.The results showed that the ignition delay time increased with equivalence ratio or CO2 dilution ratio.Fur-thermore,ignition delay time was seen to be exponentially related with the reciprocal of initial temperature.Special concern was given to the chemical effects of CO2 on the ignition delay time.The enhancement of ignition delay time with CO2 addition can be mainly ascribed to the decrease of H,O and OH radicals.The predictions of tem-perature profiles and mole fractions of CO and CO2 were strongly related to the chemical effects of CO2.A single ignition time correlation was obtained in form of Arrhenius-type for the entire range of conditions as a function of temperature,CH4 mole fraction and O2 mole fraction.This correlation could successfully capture the complex be-haviors of ignition of CH4/air/CO2 mixture.The results can be applied to MILD combustion as ＂reference time＂,for example,to predict ignition delay time in turbulent reacting flow.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10674114 and 10604045)
文摘Employing the two-state model and the time-dependent wave packet method, we have investigated the influences of the parameters of the intense femtosecond laser field on the evolution of the wave packet, as well as the population of ground and double-minimum electronic states of the NaRb molecule. For the different laser wavelengths, the evolution of the wave packet of 6{ }^1／Sigma ^ ＋ state with time and internuclear distance is different, and the different laser intensity brings different influences on the population of the electronic states of the NaRb molecule. One can control the evolutions of wave packet and the population in each state by varying the laser parameters appropriately, which will be a benefit for the light manipulation of atomic and molecular processes.
文摘A new moving or dynamic thermal tensioning technique-welding with trailing intense cooling was numerically simulated by finite element method(FEM)and experimentally investigated.The simulation results indicate that trailing intense cooling can increase significantly the longitudinal tensile plastic strain within the weld and its adjacent zone during cooling stage,which can partially or completely counterbalance the longitudinal compressive plastic strain formed in the heating stage and the solidification shrinkage formed in the cooling stage.Therefore the longitudinal shrinkage remaining in the weld and the adjacent zone is greatly reduced,which means that the residual stresses in the weldments are kept in a lower value and the residual distortion can be mitigated effectively.Meanwhile a series of parametric studies were conducted to demonstrate the influences of several key parameters such as cooling distance, cooling power and cooling width on the effectiveness of distortion control.Experimental results also verify the effectiveness of this distortion control technique and the reliability of the numerical simulation.
基金This work is supported by the National Natural Science Foundation of China(Grant No.11675075)the Natural Science Foundation of Hunan Province,China(Grant No.2018JJ2315)W.L.appreciates support from the Youth Talent Project of Hunan Province,China(Grant No.2018RS3096).
文摘^(62,64)Cu are radioisotopes of medical interest that can be used for positron emission tomography(PET)imaging.Moreover,64Cu hasβ−decay characteristics that allowfor targeted radiotherapy of cancer.In the present work,a novel approach to experimentally demonstrate the production of ^(62,64)Cu isotopes fromphotonuclear reactions is proposed in which large-current laser-based electron(e−)beams are generated fromthe interaction between sub-petawatt laser pulses and near-critical-density plasmas.According to simulations,at a laser intensity of 3.431021 W/cm2,a dense e−beamwith a total charge of 100 nCcan be produced,and this in turn produces bremsstrahlung radiation of the order of 1010 photons per laser shot,in the region of the giant dipole resonance.The bremsstrahlung radiation is guided to a natural Cu target,triggering photonuclear reactions to produce themedical isotopes ^(62,64)Cu.An optimal target geometry is employed to maximize the photoneutron yield,and ^(62,64)Cuwith appropriate activities of 0.18 GBq and 0.06 GBq are obtained for irradiation times equal to their respective half-livesmultiplied by three.The detection of the characteristic energy for the nuclear transitions of ^(62,64)Cu is also studied.The results of our calculations support the prospect of producing PET isotopes with gigabecquerel-level activity(equivalent to the required patient dose)using upcoming high-intensity laser facilities.
基金This work was supported by the National Natural Science Foundation of China(NSFC Grant Nos.11435015 and 11505251).
文摘High-energy electron radiography(HEER)is a promising diagnostic tool for high-energy-density physics,as an alternative to tools such as X/γ-ray shadowgraphy and high-energy proton radiography.Impressive progress has been made in the development and application ofHEER in the past fewyears,and its potential for high-resolution imaging of static opaque objects has been proved.In this study,by taking advantage of the short pulse duration and tunable time structure of high-energy electron probes,time-resolved imaging measurements of high-energy-density gold irradiated by ultrashort intense laser pulses are performed.Phenomena at different time scales frompicoseconds to microseconds are observed,thus proving the feasibility of this technique for imaging of static and dynamic objects.
