Laser-induced electro-response(LIER),as a new method that complements conventional rock physics testing techniques,is expected to address issues such as of unclear mechanisms,model deficiency,inconsistent evaluation p...Laser-induced electro-response(LIER),as a new method that complements conventional rock physics testing techniques,is expected to address issues such as of unclear mechanisms,model deficiency,inconsistent evaluation parameters,and difficulty in separating multiple coupling factors in shale anisotropy evaluation,and establish a more complete and reliable shale physical property evaluation system.A testing strategy for out of plane anisotropy(OPA)was proposed for characterising anisotropy by LIER,where the near infrared(NIR)continuous laser(CL)and nanosecond pulsed laser(PL)were used to irradiate the surface of oblique cut shale,and the transverse LIER of the surface was measured.A LIER detection model is constructed from the laser-thermal effect,residual transverse polarization electric field and thermionic emission transport mechanism,which is strongly relying on laser power,bias voltage,and inclination angle of the measurement direction relative to the bedding plane of shale.For OPA test on the slice of oblique cut shale under CL irradiation,the relationship between the product of LIER simulation parameters and the tilting angle can be described by a cubic function and an impulse function with a maximum value at the threshold angle.In addition,the thermal accumulation and transient thermal effects are induced in the shale under a high-energy short laser pulse irradiation,and the simulation results indicate that there is an exponential relationship between the product of parameters in the LIER model and the tilt angle.Thus,for OPA test under CL and PL irradiations,it is recommended to use the product of parameters as an evaluation index for shale anisotropy.Furthermore,to solve the problem of multiple influencing factors entangled in the exponential term of the LIER model,the tangential LIER measurement was performed on the side of cylindrical shale core,where the provided LIER model effectively presented the anisotropy of tight shale plug,especially the effects of bias voltage and laser power on LIER were relatively separated as independent variables.Finally,the LIER at the end of laser drilling is presented well using the optimized model under a focused ns NIR PL irradiation,indicating that LIER is expected to be a real-time means for characterizing shale anisotropy during laser drilling processes.These results show that the present work is fundamental for the precise evaluation and effective development of anisotropic shale reservoirs,and will drive the advances of LIER in the exploration for shale oil and gas.展开更多
The spatiotemporal distribution of soot concentration in aero-engine combustor is important for assessing its combustion performance.Here,we report experimental measurements of soot concentration in terms of Soot Volu...The spatiotemporal distribution of soot concentration in aero-engine combustor is important for assessing its combustion performance.Here,we report experimental measurements of soot concentration in terms of Soot Volume Fraction(SVF)and its spatiotemporal distribution in a single-sector dual-swirl aero-engine combustor using Two-Color Laser-Induced Incandescence(2C-LII).It is shown that soot predominantly forms in the symmetrical vortices of the primary combustion zone,exhibiting a V-type distribution with higher concentration in the lower half of the zone than the upper half,with a small amount distributed in the secondary recirculation zone.Soot emissions at the combustor outlet are relatively low under three typical operating conditions by LII experiments,which is aligned with Smoke Number(SN)from gas analysis.The effect of inlet air temperature on SVF distribution and dynamics in the primary combustion zone is studied,which suggests that the SVF level in the primary combustion zone monotonically increases with the temperature.Meanwhile,the SVF distribution becomes more symmetrical as the inlet temperature increases,although the overall SVF level in the lower half of the zone is still higher.We also investigate the influence of the inlet air pressure on the SVF distribution at the combustor outlet.The soot concentration at the combustor outlet increases with inlet pressure,mainly distributed irregularly across both sides and the center.On both sides,the distribution is continuous,while the center exhibits dot-like and linear patterns.Numerical simulations correlated SVF distribution with the flow field in the primary combustion zone,qualitatively explaining the observed SVF distribution behavior.These results under various conditions can provide valuable insights for improving the performance of this specific combustor and designing high-temperature-rise combustors in the future.展开更多
Extreme environments challenge the structural health monitoring of advanced equipment.In-situ dynamic tracking temperature is of particular value due to its enormous impact on material properties.However,the realizati...Extreme environments challenge the structural health monitoring of advanced equipment.In-situ dynamic tracking temperature is of particular value due to its enormous impact on material properties.However,the realization of such integrated temperature sensors typically requires complicated layer-by-layer molding and sintering processes including additional thermal barrier coatings.Herein,we report a laser-induced in-situ conductive passivation strategy for the fabrication of a thin-film based wide-range temperature sensor.The instantaneous thermal effect of laser irradiation creates crystalline conductive traces in response to temperature variations.Synchronously,it also allows the formation of an amorphous antioxidative layer without necessitating extra protective coatings.Such configuration enables precise real-time sensing across-50℃to 950℃following the Steinhart-Hart equation.It also exhibits durable performance with only 1.2%drift over 20 hours during long-term high-temperature,instant thermal shock,frequent wearing,and severe vibration.This in-situ,facile laser manufacturing strategy holds great promise in structural health monitoring and fault diagnosis for advanced equipment working in extreme environments.展开更多
Laser-Induced Graphene (LIG) is regarded as a promising sensor carrier due to its inherent three-dimensional porous structure. However, as two mutually exclusive properties of the pressure sensor, sensitivity and work...Laser-Induced Graphene (LIG) is regarded as a promising sensor carrier due to its inherent three-dimensional porous structure. However, as two mutually exclusive properties of the pressure sensor, sensitivity and working range are difficult to be further improved by the single porous structure. Inspired by the unique geometry of Oxalis corniculata L. leaves, we here propose a novel method consist of laser pre-etching and inducing steps to fabricate LIG-based electrodes with a two-stage architecture featuring microjigsaw and microporous structures. The following injection of liquid-silicone significantly improves the friction resistance and bending reliability of LIG materials. The interface contact between external microjigsaw structures induces substantial resistance changes, and the internal microporous structure exhibits reversibility during dynamic deformation. Consequently, the jigsaw-like pressure sensor achieves a balanced performance with sensitivities of 3.64, 1.20 and 0.03 kPa^(- 1) in pressure range of 0 -20, 20 - 40 and 40 - 150 kPa, respectively. The bionic LIG-based pressure sensor serves as the core component and further integrated with an all-in-one wireless transmission system capable of monitoring various health parameters such as subtle pulse rates, heartbeat rhythms, sounds, etc., indicating broad prospects in future wearable electronics.展开更多
Quantitative measurement of Soot Volume Fraction (SVF) is an essential prerequisite for controlling soot particle emissions from aero-engine combustors. As an in-situ and non-intrusive optical diagnostic technique, La...Quantitative measurement of Soot Volume Fraction (SVF) is an essential prerequisite for controlling soot particle emissions from aero-engine combustors. As an in-situ and non-intrusive optical diagnostic technique, Laser-Induced Incandescence (LII) has been increasingly applied for soot concentration quantification in various combustion environments such as laminar flame, vehicle exhaust, internal combustion chamber as well as aero-engine combustor. In this work, we experimentally measured the spatial and temporal distribution of SVF using two-color LII technique at the outlet of a single-sector dual-swirl aero-engine model combustor. The effect of inlet pressure and air preheat temperature on the SVF distribution was separately investigated within a pressure range of 241–425 kPa and a temperature range of 292–500 K. The results show that soot production increases with the inlet pressure but generally decreases with the air preheat temperature. Qualitative analysis was provided to explain the above results of parametric studies. The LII experiments were also conducted under 3 designed conditions to evaluate soot emission under practical operations. Particularly, weak soot emission was detected at the outlet under the idle condition. Our experimental results provide a valuable benchmark for evaluating soot emission in the exhaust plume of this aero-engine combustor during practical operations.展开更多
We present a fully time-dependent quantum wave packet evolution method for investigating molecular dynamics in intense laser fields.This approach enables the simultaneous treatment of interactions among multiple elect...We present a fully time-dependent quantum wave packet evolution method for investigating molecular dynamics in intense laser fields.This approach enables the simultaneous treatment of interactions among multiple electronic states while simultaneously tracking their time-dependent electronic,vibrational,and rotational dynamics.As an illustrative example,we consider neutral H_(2)molecules and simulate the laser-induced excitation dynamics of electronic and rotational states in strong laser fields,quantitatively distinguishing the respective contributions of electronic dipole transitions(within the classical-field approximation)and non-resonant Raman processes to the overall molecular dynamics.Furthermore,we precisely evaluate the relative contributions of direct tunneling ionization from the ground state and ionization following electronic excitation in the strong-field ionization of H_(2).The developed methodology shows strong potential for performing high-precision theoretical simulations of electronic-vibrational-rotational state excitations,ionization,and dissociation dynamics in molecules and their ions under intense laser fields.展开更多
The Görtler vortex is a characteristic flow feature observed in the boundary layer on compression ramp in hypersonic flow.In the context of high-enthalpy plasma flows during aerospace re-entry processes,there is ...The Görtler vortex is a characteristic flow feature observed in the boundary layer on compression ramp in hypersonic flow.In the context of high-enthalpy plasma flows during aerospace re-entry processes,there is currently a lack of effective means to visualize the boundary layer.In this study,the Nitric Oxide Planar Laser-Induced Fluorescence(NO-PLIF)technique was employed to visualize the boundary layer of a compression ramp in a 50-MW arc-heated plasma wind tunnel.Görtler-like vortex structures were observed in the boundary layer of the ramp.This is the first time that Görtler vortices have been clearly observed in a high-enthalpy plasma flow.By varying the flow conditions,the Görtler vortices persisted in the boundary layer of the ramp when the total enthalpy of the arc-heated wind tunnel exceeded 12.3 MJ/kg.Several image processing techniques were applied to extract the structure of high-speed Görtler streaks,and the position of the high-speed streaks was found to be non-fixed,whereas the average Görtler wavelength remained at approximately 30 mm at a 10°ramp and showed limited variation with the total enthalpy.Additionally,a sheet-forming optics system with an adjustable angle and height was designed to enable visualization of the Görtler vortices in the boundary layer of the ramp at different angles and heights.The vortices on the low-angle ramp exhibited better stability and shorter wavelengths.Visualization results at different heights confirmed that the Görtler vortex wavelength was approximately twice the boundary layer thickness.This study demonstrates the feasibility and potential of the PLIF technique for the visualization of the boundary layer in plasma flows,especially with regard to Görtler vortices.展开更多
Laser debonding technology has been widely used in advanced chip packaging,such as fan-out integration,2.5D/3D ICs,and MEMS devices.Typically,laser debonding of bonded pairs(R/R separation)is typically achieved by com...Laser debonding technology has been widely used in advanced chip packaging,such as fan-out integration,2.5D/3D ICs,and MEMS devices.Typically,laser debonding of bonded pairs(R/R separation)is typically achieved by completely removing the material from the ablation region within the release material layer at high energy densities.However,this R/R separation method often results in a significant amount of release material and carbonized debris remaining on the surface of the device wafer,severely reducing product yields and cleaning efficiency for ultra-thin device wafers.Here,we proposed an interfacial separation strategy based on laser-induced hot stamping effect and thermoelastic stress wave,which enables stress-free separation of wafer bonding pairs at the interface of the release layer and the adhesive layer(R/A separation).By comprehensively analyzing the micro-morphology and material composition of the release material,we elucidated the laser debonding behavior of bonded pairs under different separation modes.Additionally,we calculated the ablation threshold of the release material in the case of wafer bonding and established the processing window for different separation methods.This work offers a fresh perspective on the development and application of laser debonding technology.The proposed R/A interface separation method is versatile,controllable,and highly reliable,and does not leave release materials and carbonized debris on device wafers,demonstrating strong industrial adaptability,which greatly facilitates the application and development of advanced packaging for ultra-thin chips.展开更多
Alkoxy radicals bearing cyclic substituents are oxidation intermediates of important hydrocarbon compounds in atmospheric chemistry and pharmacology.Spectroscopic study can provide diagnostic methods for monitoring th...Alkoxy radicals bearing cyclic substituents are oxidation intermediates of important hydrocarbon compounds in atmospheric chemistry and pharmacology.Spectroscopic study can provide diagnostic methods for monitoring these radicals in reactions and investigating their structure-reactivity effect.In this work,vibrationally resolved laser-induced fluorescence(LIF)spectrum of the 3-cyclohexyl-1-propoxy radical was obtained in supersonic jet condition.Low energy conformers G′_(1)T_(2)G_(3)and T_(1)T_(2)G_(3)were identified as the spectral carriers.A red shift of the spectrum compared to that of the straight chain alkoxy radical with same number of carbon atoms suggested that the cyclohexyl ring was a slightly better electron donor than the linear alkyl group.Studies also showed that theαandβC cyclohexyl substitutions significantly weakened theβC-C bonds of the radicals,and conversely,the strength of the C-C bonds on cyclohexyl ring decreased as its distance from the O radical decreased.When cyclohexyl substitution occurred atγC,the stability of the 3-cyclohexyl-1-propoxy radical became comparable to that of straight chain alkoxy radicals.展开更多
Femtosecond laser-induced periodic surface structures(LIPSS)have been extensively studied over the past few decades.In particular,the period and groove width of high-spatial-frequency LIPSS(HSFL)is much smaller than t...Femtosecond laser-induced periodic surface structures(LIPSS)have been extensively studied over the past few decades.In particular,the period and groove width of high-spatial-frequency LIPSS(HSFL)is much smaller than the diffraction limit,making it a useful method for efficient nanomanufacturing.However,compared with the low-spatial-frequency LIPSS(LSFL),the structure size of the HSFL is smaller,and it is more easily submerged.Therefore,the formation mechanism of HSFL is complex and has always been a research hotspot in this field.In this study,regular LSFL with a period of 760 nm was fabricated in advance on a silicon surface with two-beam interference using an 800 nm,50 fs femtosecond laser.The ultrafast dynamics of HSFL formation on the silicon surface of prefabricated LSFL under single femtosecond laser pulse irradiation were observed and analyzed for the first time using collinear pump-probe imaging method.In general,the evolution of the surface structure undergoes five sequential stages:the LSFL begins to split,becomes uniform HSFL,degenerates into an irregular LSFL,undergoes secondary splitting into a weakly uniform HSFL,and evolves into an irregular LSFL or is submerged.The results indicate that the local enhancement of the submerged nanocavity,or the nanoplasma,in the prefabricated LSFL ridge led to the splitting of the LSFL,and the thermodynamic effect drove the homogenization of the splitting LSFL,which evolved into HSFL.展开更多
Integration of sensors with engineering thermoplastics allows to track their health and surrounding stimuli.As one of vital backbones to construct sensor systems,copper(Cu)is highly conductive and cost-effective,yet t...Integration of sensors with engineering thermoplastics allows to track their health and surrounding stimuli.As one of vital backbones to construct sensor systems,copper(Cu)is highly conductive and cost-effective,yet tends to easily oxidize during and after processing.Herein,an in-situ integrated sensor system on engineering thermoplastics via hybrid laser direct writing is proposed,which primarily consists of laser-passivated functional Cu interconnects and laser-induced carbon-based sensors.Through a one-step photothermal treatment,the resulting functional Cu interconnects after reductive sintering and passivation are capable of resisting long-term oxidation failure at high temperatures(up to 170℃)without additional encapsulations.Interfacing with signal processing units,such an all-in-one system is applied for long-term and real-time temperature monitoring.This integrated sensor system with facile laser manufacturing strategies holds potentials for health monitoring and fault diagnosis of advanced equipment such as aircrafts,automobiles,high-speed trains,and medical devices.展开更多
Herein,we unveil the intelligent detection of multiple catechol isomers in complex environments utilizing both laser-induced graphene(LIG)and artificial neural network(ANN).The large scale-up manufacturing of LIG-base...Herein,we unveil the intelligent detection of multiple catechol isomers in complex environments utilizing both laser-induced graphene(LIG)and artificial neural network(ANN).The large scale-up manufacturing of LIG-based sensors(LIGS)with three-electrode configuration on polyimide(PI)is achieved by direct laser-writing and screen-printing technologies.Our LIGS shows excellent electrochemical performance toward catechol isomers,i.e.,hydroquinone(1,4-dihydroxybenzene,HQ),catechol(1,2-dihydroxybenzene,CT),and resorcinol(1,3-dihydroxybenzene,RC),with a low limit of detection(LOD)(CC,0.079μmol/L;HQ,0.093μmol/L;RC,1.18μmol/L).Moreover,the ANN model is developed for machine-intelligent to predict concentrations of catechol isomers under an interfering environment via a single LIGS.Using six unique parameters extracted from the differential pulse voltammetry(DPV)response,the machine learning-based regression provides a coefficient of correlation with 0.998 and is able to correctly predict the total and individual concentrations in complex river samples.Hence,this work provides a guide for the preparation and application of LIGS via facile and cost-efficient mass production and the development of an intelligent sensing platform based on the ANN model.展开更多
Laser-induced breakdown spectroscopy(LIBS)has become a widely used atomic spectroscopic technique for rapid coal analysis.However,the vast amount of spectral information in LIBS contains signal uncertainty,which can a...Laser-induced breakdown spectroscopy(LIBS)has become a widely used atomic spectroscopic technique for rapid coal analysis.However,the vast amount of spectral information in LIBS contains signal uncertainty,which can affect its quantification performance.In this work,we propose a hybrid variable selection method to improve the performance of LIBS quantification.Important variables are first identified using Pearson's correlation coefficient,mutual information,least absolute shrinkage and selection operator(LASSO)and random forest,and then filtered and combined with empirical variables related to fingerprint elements of coal ash content.Subsequently,these variables are fed into a partial least squares regression(PLSR).Additionally,in some models,certain variables unrelated to ash content are removed manually to study the impact of variable deselection on model performance.The proposed hybrid strategy was tested on three LIBS datasets for quantitative analysis of coal ash content and compared with the corresponding data-driven baseline method.It is significantly better than the variable selection only method based on empirical knowledge and in most cases outperforms the baseline method.The results showed that on all three datasets the hybrid strategy for variable selection combining empirical knowledge and data-driven algorithms achieved the lowest root mean square error of prediction(RMSEP)values of 1.605,3.478 and 1.647,respectively,which were significantly lower than those obtained from multiple linear regression using only 12 empirical variables,which are 1.959,3.718 and 2.181,respectively.The LASSO-PLSR model with empirical support and 20 selected variables exhibited a significantly improved performance after variable deselection,with RMSEP values dropping from 1.635,3.962 and 1.647 to 1.483,3.086 and 1.567,respectively.Such results demonstrate that using empirical knowledge as a support for datadriven variable selection can be a viable approach to improve the accuracy and reliability of LIBS quantification.展开更多
Electrochemical production of hydrogen from water requires the development ofelectrocatalysts that are active,stable,and low-cost for water splitting.To address these challenges,researchers are increasingly exploring ...Electrochemical production of hydrogen from water requires the development ofelectrocatalysts that are active,stable,and low-cost for water splitting.To address these challenges,researchers are increasingly exploring binder-free electrocatalytic integratedelectrodes (IEs) as an alternative to conventional powder-based electrode preparation methods,for the former is highly desirable to improve the catalytic activity and long-term stability for large-scale applications of electrocatalysts.Herein,we demonstrate a laser-inducedhydrothermal reaction (LIHR) technique to grow NiMoO4nanosheets on nickel foam,which is then calcined under H2/Ar mixed gases to prepare the IE IE-NiMo-LR.This electrode exhibits superior hydrogen evolution reaction performance,requiring overpotentials of 59,116 and143 mV to achieve current densities of 100,500 and 1000 mA·cm-2.During the 350 h chronopotentiometry test at current densities of 100 and 500 m A·cm-2,the overpotentialremains essentially unchanged.In addition,NiFe-layered double hydroxide grown on Ni foam is also fabricated with the same LIHR method and coupled with IE-NiMo-IR to achieve water splitting.This combination exhibits excellent durability under industrial current density.The energy consumption and production efficiency of the LIHR method are systematicallycompared with the conventional hydrothermal method.The LIHR method significantly improves the production rate by over 19 times,while consuming only 27.78%of the total energy required by conventional hydrothermal methods to achieve the same production.展开更多
The matrix thermal properties have an important impact on laser-induced plasma,as the thermal effect dominates the interaction between ns-pulsed laser and matter,especially in metals.We used a series of pure metals an...The matrix thermal properties have an important impact on laser-induced plasma,as the thermal effect dominates the interaction between ns-pulsed laser and matter,especially in metals.We used a series of pure metals and aluminum alloys to measure plasma temperature and electron density through laser-induced breakdown spectroscopy,in order to investigate the effect of matrix thermal properties on laser-induced plasma.In pure metals,a significant negative linear correlation was observed between the matrix thermal storage coefficient and plasma temperature,while a weak correlation was observed with electron density.The results indicate that metals with low thermal conductivity or specific heat capacity require less laser energy for thermal diffusion or melting and evaporation,resulting in higher ablation rates and higher plasma temperatures.However,considering ionization energy,thermal effects may be a secondary factor affecting electron density.The experiment of aluminum alloy further confirms the influence of thermal conductivity on plasma temperature and its mechanism explanation.展开更多
Rapid online analysis of liquid slag is essential for optimizing the quality and energy efficiency of steel production. To investigate the key factors that affect the online measurement of refined slag using laser-ind...Rapid online analysis of liquid slag is essential for optimizing the quality and energy efficiency of steel production. To investigate the key factors that affect the online measurement of refined slag using laser-induced breakdown spectroscopy(LIBS), this study examined the effects of slag composition and temperature on the intensity and stability of the LIBS spectra. The experimental temperature was controlled at three levels: 1350℃, 1400℃, and 1450℃. The results showed that slag composition and temperature significantly affected the intensity and stability of the LIBS spectra. Increasing the Fe content and temperature in the slag reduces its viscosity, resulting in an enhanced intensity and stability of the LIBS spectra. Additionally, 42 refined slag samples were quantitatively analyzed for Fe, Si, Ca, Mg, Al, and Mn at 1350℃, 1400℃, and 1450℃.The normalized full spectrum combined with partial least squares(PLS) quantification modeling was used, using the Ca Ⅱ 317.91 nm spectral line as an internal standard. The results show that using the internal standard normalization method can significantly reduce the influence of spectral fluctuations. Meanwhile, a temperature of 1450℃ has been found to yield superior results compared to both 1350℃ and 1400℃, and it is advantageous to conduct a quantitative analysis of the slag when it is in a “water-like” state with low viscosity.展开更多
The excellent performance of laser-induced removal has been widely recognized,yet the limitation of its applications has been gradually approached for complex multilayer coatings in practical situations.Therefore,it i...The excellent performance of laser-induced removal has been widely recognized,yet the limitation of its applications has been gradually approached for complex multilayer coatings in practical situations.Therefore,it is necessary to clarify the laser-induced removal mechanisms of different material layers,which may contribute to guiding precise and controllable layer-by-layer removal and subsequent repair.Herein,the laser-induced layer-by-layer removal of FeCo-based multilayer wave-absorbing coatings was designed and verified.The macro/micro morphologies and elemental analysis indicated that the removal of the topcoat and wave-absorbing layer was dominated by thermal ablation.Interestingly,experiments and simulations demonstrated that a shift in the removal mechanism,i.e.,from the ablation mechanism to the stripping mechanism,occurred when the laser irradiated the primer.It is mainly attributed to the competing contributions of temperature rise and thermal stress to the removal effect.Subsequent macrodynamic behavior captured by a high-speed camera also validated the combination of both re-moval mechanisms.Additionally,the evolution of the crystalline phase and element valence state was revealed.Further laser-induced breakdown spectroscopy revealed the microscopic material motions dur-ing the layer-by-layer removal,including molecular bond breaking induced by multiphoton absorption,atomic ionization,excitation and compounding of electrons and ions,crystal lattice deformation caused by electron-phonon coupling,etc.Based on the above analysis,the thermo-mechanical action mechanisms and microscopic motion models of laser-induced layer-by-layer removal for FeCo-based multilayer wave-absorbing coatings were established,which is expected to be an ideal method for breaking through the limitation of laser-induced removal’s applications.展开更多
Surface-enhanced Raman spectroscopy(SERS)microfluidic system,which enables rapid detection of chemical and biological analytes,offers an effective platform to monitor various food contaminants and disease diagnoses.Th...Surface-enhanced Raman spectroscopy(SERS)microfluidic system,which enables rapid detection of chemical and biological analytes,offers an effective platform to monitor various food contaminants and disease diagnoses.The efficacy of SERS microfluidic systems is greatly dependent on the sensitivity and reusability of SERS detection substrates to ensure repeated use for prolonged periods.This study proposed a novel process of femtosecond laser nanoparticle array(NPA)implantation to achieve homogeneous forward transfer of gold NPA on a flexible polymer film and accurately integrated it within microfluidic chips for SERS detection.The implanted Au-NPA strips show a remarkable electromagnetic field enhancement with the factor of 9×108 during SERS detection of malachite green(MG)solution,achieving a detection limit lower than 10 ppt,far better than most laser-prepared SERS substrates.Furthermore,Au-NPA strips show excellent reusability after several physical and chemical cleaning,because of the robust embedment of laser-implanted NPA in flexible substrates.To demonstrate the performance of Au-NPA,a SERS microfluidic system is built to monitor the online oxidation reaction between MG/NaClO reactants,which helps infer the reaction path.The proposed method of nanoparticle implantation is more effective than the direct laser structuring technique.It provides better performance for SERS detection,robustness of detection,and substrate flexibility and has a wider range of applications for microfluidic systems without any negative impact.展开更多
It is challenging to cooperatively improve the nonlinear optical(NLO)efficiency and the laser-induced damage threshold(LIDT).This work reports a novel IR NLO materials CsInP_(2)S_(7)(CIPS)designed by combination the s...It is challenging to cooperatively improve the nonlinear optical(NLO)efficiency and the laser-induced damage threshold(LIDT).This work reports a novel IR NLO materials CsInP_(2)S_(7)(CIPS)designed by combination the strategies of alkali metals substitution and microscopic NLO units PS4 introduction based on AgGaS_(2).CIPS was composed of strongly distorted[InS_(6)]^(9-)octahedra and[P_(2)S_(7)]4-dimers constructed by corner-sharing[PS_(4)]^(3-),which increase the NLO efficiency and decrease thermal expansion anisotropy simultaneously.Compared with AgGaS_(2),CIPS exhibited strong phase matchable NLO response ca.1.1×AGS@2.1μm,high LIDT ca.20.8×AgGaS_(2),and IR transparency up to 15.3μm.Structural analysis and theoretical investigation confirmed that large SHG effect and ultrahigh LIDT of CIPS originated from the synergistic contribution of[InS_(6)]^(9-)octahedra and[P_(2)S_(7)]4-dimers.These results indicate that CIPS is a promising NLO candidate in the mid-IR region,and this study provides a new approach for developing potential NLO-LIDT compatible materials.展开更多
Two-dimensional diagnosis of laser-induced zirconium(Zr)plasma has been experimentally performed using the time-of-flight method by employing Faraday cups in addition to electric and magnetic probes.The characteristic...Two-dimensional diagnosis of laser-induced zirconium(Zr)plasma has been experimentally performed using the time-of-flight method by employing Faraday cups in addition to electric and magnetic probes.The characteristic parameters of laser-induced Zr plasma have been evaluated as a function of different laser irradiances ranging from 4.5 to 11.7 GW cm-2 at different axial positions of 1–4 cm with a fixed radial distance of 2 cm.A well-supporting correlation between the plume parameters and the laser-plasma-produced spontaneous electric and magnetic(E and B)fields was established.The measurements of the characteristic parameters and spontaneously induced fields were observed to have an increasing trend with the increasing laser irradiance.However,when increasing the spatial distance in both the axial and radial directions,the plasma parameters(electron/ion number density,temperature and kinetic energy)did not show either continuously increasing or decreasing trends due to various kinetic and dynamic processes during the spatial evolution of the plume.However,the E and B fields were observed to be always diffusing away from the target.The radial component of electron number densities remained higher than the axial number density component,whereas the axial ion number density at all laser irradiances and axial distances remained higher than the radial ion number density.The higher axial self-generated electric field(SGEF)values than radial SGEF values are correlated with the effective charge-separation mechanism of electrons and ions.The generation of a self-generated magnetic field is observed dominantly in the radial direction at increasing laser irradiance as compared to the axial one due to the deflection of fast-moving electrons and the persistence of two-electron temperature on the radial axis.展开更多
基金supported by the National Natural Science Foundation of China(Nos.12374412 and 12404502).
文摘Laser-induced electro-response(LIER),as a new method that complements conventional rock physics testing techniques,is expected to address issues such as of unclear mechanisms,model deficiency,inconsistent evaluation parameters,and difficulty in separating multiple coupling factors in shale anisotropy evaluation,and establish a more complete and reliable shale physical property evaluation system.A testing strategy for out of plane anisotropy(OPA)was proposed for characterising anisotropy by LIER,where the near infrared(NIR)continuous laser(CL)and nanosecond pulsed laser(PL)were used to irradiate the surface of oblique cut shale,and the transverse LIER of the surface was measured.A LIER detection model is constructed from the laser-thermal effect,residual transverse polarization electric field and thermionic emission transport mechanism,which is strongly relying on laser power,bias voltage,and inclination angle of the measurement direction relative to the bedding plane of shale.For OPA test on the slice of oblique cut shale under CL irradiation,the relationship between the product of LIER simulation parameters and the tilting angle can be described by a cubic function and an impulse function with a maximum value at the threshold angle.In addition,the thermal accumulation and transient thermal effects are induced in the shale under a high-energy short laser pulse irradiation,and the simulation results indicate that there is an exponential relationship between the product of parameters in the LIER model and the tilt angle.Thus,for OPA test under CL and PL irradiations,it is recommended to use the product of parameters as an evaluation index for shale anisotropy.Furthermore,to solve the problem of multiple influencing factors entangled in the exponential term of the LIER model,the tangential LIER measurement was performed on the side of cylindrical shale core,where the provided LIER model effectively presented the anisotropy of tight shale plug,especially the effects of bias voltage and laser power on LIER were relatively separated as independent variables.Finally,the LIER at the end of laser drilling is presented well using the optimized model under a focused ns NIR PL irradiation,indicating that LIER is expected to be a real-time means for characterizing shale anisotropy during laser drilling processes.These results show that the present work is fundamental for the precise evaluation and effective development of anisotropic shale reservoirs,and will drive the advances of LIER in the exploration for shale oil and gas.
基金support of the National Science and Technology Major Project of China(No.J2019-V-0005-0096)the National Key Research and Development Program of China(No.2020YFA0405700).
文摘The spatiotemporal distribution of soot concentration in aero-engine combustor is important for assessing its combustion performance.Here,we report experimental measurements of soot concentration in terms of Soot Volume Fraction(SVF)and its spatiotemporal distribution in a single-sector dual-swirl aero-engine combustor using Two-Color Laser-Induced Incandescence(2C-LII).It is shown that soot predominantly forms in the symmetrical vortices of the primary combustion zone,exhibiting a V-type distribution with higher concentration in the lower half of the zone than the upper half,with a small amount distributed in the secondary recirculation zone.Soot emissions at the combustor outlet are relatively low under three typical operating conditions by LII experiments,which is aligned with Smoke Number(SN)from gas analysis.The effect of inlet air temperature on SVF distribution and dynamics in the primary combustion zone is studied,which suggests that the SVF level in the primary combustion zone monotonically increases with the temperature.Meanwhile,the SVF distribution becomes more symmetrical as the inlet temperature increases,although the overall SVF level in the lower half of the zone is still higher.We also investigate the influence of the inlet air pressure on the SVF distribution at the combustor outlet.The soot concentration at the combustor outlet increases with inlet pressure,mainly distributed irregularly across both sides and the center.On both sides,the distribution is continuous,while the center exhibits dot-like and linear patterns.Numerical simulations correlated SVF distribution with the flow field in the primary combustion zone,qualitatively explaining the observed SVF distribution behavior.These results under various conditions can provide valuable insights for improving the performance of this specific combustor and designing high-temperature-rise combustors in the future.
基金the financial support from the National Natural Science Foundation of China(52475610,52105593)the Zhejiang Provincial Natural Science Foundation of China(LDQ24E050001)+1 种基金the"Pioneer"and"Leading Goose"R&D Program of Zhejiang(2023C03007,2024C01173)the Fundamental Research Funds for the Central Universities(226-2024-00085)。
文摘Extreme environments challenge the structural health monitoring of advanced equipment.In-situ dynamic tracking temperature is of particular value due to its enormous impact on material properties.However,the realization of such integrated temperature sensors typically requires complicated layer-by-layer molding and sintering processes including additional thermal barrier coatings.Herein,we report a laser-induced in-situ conductive passivation strategy for the fabrication of a thin-film based wide-range temperature sensor.The instantaneous thermal effect of laser irradiation creates crystalline conductive traces in response to temperature variations.Synchronously,it also allows the formation of an amorphous antioxidative layer without necessitating extra protective coatings.Such configuration enables precise real-time sensing across-50℃to 950℃following the Steinhart-Hart equation.It also exhibits durable performance with only 1.2%drift over 20 hours during long-term high-temperature,instant thermal shock,frequent wearing,and severe vibration.This in-situ,facile laser manufacturing strategy holds great promise in structural health monitoring and fault diagnosis for advanced equipment working in extreme environments.
基金supported by the Natural Science Foundation of Hunan Province,China(No.2024JJ6039).
文摘Laser-Induced Graphene (LIG) is regarded as a promising sensor carrier due to its inherent three-dimensional porous structure. However, as two mutually exclusive properties of the pressure sensor, sensitivity and working range are difficult to be further improved by the single porous structure. Inspired by the unique geometry of Oxalis corniculata L. leaves, we here propose a novel method consist of laser pre-etching and inducing steps to fabricate LIG-based electrodes with a two-stage architecture featuring microjigsaw and microporous structures. The following injection of liquid-silicone significantly improves the friction resistance and bending reliability of LIG materials. The interface contact between external microjigsaw structures induces substantial resistance changes, and the internal microporous structure exhibits reversibility during dynamic deformation. Consequently, the jigsaw-like pressure sensor achieves a balanced performance with sensitivities of 3.64, 1.20 and 0.03 kPa^(- 1) in pressure range of 0 -20, 20 - 40 and 40 - 150 kPa, respectively. The bionic LIG-based pressure sensor serves as the core component and further integrated with an all-in-one wireless transmission system capable of monitoring various health parameters such as subtle pulse rates, heartbeat rhythms, sounds, etc., indicating broad prospects in future wearable electronics.
基金supported by the National Key Research and Development Program of China(No.2020YFA0405700).
文摘Quantitative measurement of Soot Volume Fraction (SVF) is an essential prerequisite for controlling soot particle emissions from aero-engine combustors. As an in-situ and non-intrusive optical diagnostic technique, Laser-Induced Incandescence (LII) has been increasingly applied for soot concentration quantification in various combustion environments such as laminar flame, vehicle exhaust, internal combustion chamber as well as aero-engine combustor. In this work, we experimentally measured the spatial and temporal distribution of SVF using two-color LII technique at the outlet of a single-sector dual-swirl aero-engine model combustor. The effect of inlet pressure and air preheat temperature on the SVF distribution was separately investigated within a pressure range of 241–425 kPa and a temperature range of 292–500 K. The results show that soot production increases with the inlet pressure but generally decreases with the air preheat temperature. Qualitative analysis was provided to explain the above results of parametric studies. The LII experiments were also conducted under 3 designed conditions to evaluate soot emission under practical operations. Particularly, weak soot emission was detected at the outlet under the idle condition. Our experimental results provide a valuable benchmark for evaluating soot emission in the exhaust plume of this aero-engine combustor during practical operations.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1602502)the National Natural Science Foundation of China(Grant No.12450404)。
文摘We present a fully time-dependent quantum wave packet evolution method for investigating molecular dynamics in intense laser fields.This approach enables the simultaneous treatment of interactions among multiple electronic states while simultaneously tracking their time-dependent electronic,vibrational,and rotational dynamics.As an illustrative example,we consider neutral H_(2)molecules and simulate the laser-induced excitation dynamics of electronic and rotational states in strong laser fields,quantitatively distinguishing the respective contributions of electronic dipole transitions(within the classical-field approximation)and non-resonant Raman processes to the overall molecular dynamics.Furthermore,we precisely evaluate the relative contributions of direct tunneling ionization from the ground state and ionization following electronic excitation in the strong-field ionization of H_(2).The developed methodology shows strong potential for performing high-precision theoretical simulations of electronic-vibrational-rotational state excitations,ionization,and dissociation dynamics in molecules and their ions under intense laser fields.
基金supported by the National Natural Science Foundation of China(Nos.62175053,62305087)。
文摘The Görtler vortex is a characteristic flow feature observed in the boundary layer on compression ramp in hypersonic flow.In the context of high-enthalpy plasma flows during aerospace re-entry processes,there is currently a lack of effective means to visualize the boundary layer.In this study,the Nitric Oxide Planar Laser-Induced Fluorescence(NO-PLIF)technique was employed to visualize the boundary layer of a compression ramp in a 50-MW arc-heated plasma wind tunnel.Görtler-like vortex structures were observed in the boundary layer of the ramp.This is the first time that Görtler vortices have been clearly observed in a high-enthalpy plasma flow.By varying the flow conditions,the Görtler vortices persisted in the boundary layer of the ramp when the total enthalpy of the arc-heated wind tunnel exceeded 12.3 MJ/kg.Several image processing techniques were applied to extract the structure of high-speed Görtler streaks,and the position of the high-speed streaks was found to be non-fixed,whereas the average Görtler wavelength remained at approximately 30 mm at a 10°ramp and showed limited variation with the total enthalpy.Additionally,a sheet-forming optics system with an adjustable angle and height was designed to enable visualization of the Görtler vortices in the boundary layer of the ramp at different angles and heights.The vortices on the low-angle ramp exhibited better stability and shorter wavelengths.Visualization results at different heights confirmed that the Görtler vortex wavelength was approximately twice the boundary layer thickness.This study demonstrates the feasibility and potential of the PLIF technique for the visualization of the boundary layer in plasma flows,especially with regard to Görtler vortices.
基金the National Natural Science Foundation of China(62174170)the Natural Science Foundation of Guangdong Province(2024A1515010123)+4 种基金the Shenzhen Science and Technology Program(20220807020526001)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0670000)the Shenzhen Science and Technology Program(KJZD20230923114708018,KJZD20230923114710022)the Talent Support Project of Guangdong(2021TX06C101)the Shenzhen Basic Research(JCYJ20210324115406019).
文摘Laser debonding technology has been widely used in advanced chip packaging,such as fan-out integration,2.5D/3D ICs,and MEMS devices.Typically,laser debonding of bonded pairs(R/R separation)is typically achieved by completely removing the material from the ablation region within the release material layer at high energy densities.However,this R/R separation method often results in a significant amount of release material and carbonized debris remaining on the surface of the device wafer,severely reducing product yields and cleaning efficiency for ultra-thin device wafers.Here,we proposed an interfacial separation strategy based on laser-induced hot stamping effect and thermoelastic stress wave,which enables stress-free separation of wafer bonding pairs at the interface of the release layer and the adhesive layer(R/A separation).By comprehensively analyzing the micro-morphology and material composition of the release material,we elucidated the laser debonding behavior of bonded pairs under different separation modes.Additionally,we calculated the ablation threshold of the release material in the case of wafer bonding and established the processing window for different separation methods.This work offers a fresh perspective on the development and application of laser debonding technology.The proposed R/A interface separation method is versatile,controllable,and highly reliable,and does not leave release materials and carbonized debris on device wafers,demonstrating strong industrial adaptability,which greatly facilitates the application and development of advanced packaging for ultra-thin chips.
基金supported by the National Natural Science Foundation of China(No.22173012 and No.21773011).
文摘Alkoxy radicals bearing cyclic substituents are oxidation intermediates of important hydrocarbon compounds in atmospheric chemistry and pharmacology.Spectroscopic study can provide diagnostic methods for monitoring these radicals in reactions and investigating their structure-reactivity effect.In this work,vibrationally resolved laser-induced fluorescence(LIF)spectrum of the 3-cyclohexyl-1-propoxy radical was obtained in supersonic jet condition.Low energy conformers G′_(1)T_(2)G_(3)and T_(1)T_(2)G_(3)were identified as the spectral carriers.A red shift of the spectrum compared to that of the straight chain alkoxy radical with same number of carbon atoms suggested that the cyclohexyl ring was a slightly better electron donor than the linear alkyl group.Studies also showed that theαandβC cyclohexyl substitutions significantly weakened theβC-C bonds of the radicals,and conversely,the strength of the C-C bonds on cyclohexyl ring decreased as its distance from the O radical decreased.When cyclohexyl substitution occurred atγC,the stability of the 3-cyclohexyl-1-propoxy radical became comparable to that of straight chain alkoxy radicals.
基金supports from the National Natural Science Foundation of China(12074123,12174108)the Foundation of‘Manufacturing beyond limits’of Shanghai‘Talent Program'of Henan Academy of Sciences.
文摘Femtosecond laser-induced periodic surface structures(LIPSS)have been extensively studied over the past few decades.In particular,the period and groove width of high-spatial-frequency LIPSS(HSFL)is much smaller than the diffraction limit,making it a useful method for efficient nanomanufacturing.However,compared with the low-spatial-frequency LIPSS(LSFL),the structure size of the HSFL is smaller,and it is more easily submerged.Therefore,the formation mechanism of HSFL is complex and has always been a research hotspot in this field.In this study,regular LSFL with a period of 760 nm was fabricated in advance on a silicon surface with two-beam interference using an 800 nm,50 fs femtosecond laser.The ultrafast dynamics of HSFL formation on the silicon surface of prefabricated LSFL under single femtosecond laser pulse irradiation were observed and analyzed for the first time using collinear pump-probe imaging method.In general,the evolution of the surface structure undergoes five sequential stages:the LSFL begins to split,becomes uniform HSFL,degenerates into an irregular LSFL,undergoes secondary splitting into a weakly uniform HSFL,and evolves into an irregular LSFL or is submerged.The results indicate that the local enhancement of the submerged nanocavity,or the nanoplasma,in the prefabricated LSFL ridge led to the splitting of the LSFL,and the thermodynamic effect drove the homogenization of the splitting LSFL,which evolved into HSFL.
基金STI 2030-Major Projects(2022ZD0208601)National Natural Science Foundation of China(52105593)+2 种基金Zhejiang Provincial Natural Science Foundation of China(LDQ24E050001)‘Pioneer’and‘Leading Goose’R&D Program of Zhejiang(2023C01051)Fundamental Research Funds for the Central Universities(226-2024-00085)。
文摘Integration of sensors with engineering thermoplastics allows to track their health and surrounding stimuli.As one of vital backbones to construct sensor systems,copper(Cu)is highly conductive and cost-effective,yet tends to easily oxidize during and after processing.Herein,an in-situ integrated sensor system on engineering thermoplastics via hybrid laser direct writing is proposed,which primarily consists of laser-passivated functional Cu interconnects and laser-induced carbon-based sensors.Through a one-step photothermal treatment,the resulting functional Cu interconnects after reductive sintering and passivation are capable of resisting long-term oxidation failure at high temperatures(up to 170℃)without additional encapsulations.Interfacing with signal processing units,such an all-in-one system is applied for long-term and real-time temperature monitoring.This integrated sensor system with facile laser manufacturing strategies holds potentials for health monitoring and fault diagnosis of advanced equipment such as aircrafts,automobiles,high-speed trains,and medical devices.
基金supported by the National Natural Science Foundation of China(Nos.22274053 and 22274051)the Shanghai Municipal Science and Technology Major Project(“Beyond Limits Manufacture”)。
文摘Herein,we unveil the intelligent detection of multiple catechol isomers in complex environments utilizing both laser-induced graphene(LIG)and artificial neural network(ANN).The large scale-up manufacturing of LIG-based sensors(LIGS)with three-electrode configuration on polyimide(PI)is achieved by direct laser-writing and screen-printing technologies.Our LIGS shows excellent electrochemical performance toward catechol isomers,i.e.,hydroquinone(1,4-dihydroxybenzene,HQ),catechol(1,2-dihydroxybenzene,CT),and resorcinol(1,3-dihydroxybenzene,RC),with a low limit of detection(LOD)(CC,0.079μmol/L;HQ,0.093μmol/L;RC,1.18μmol/L).Moreover,the ANN model is developed for machine-intelligent to predict concentrations of catechol isomers under an interfering environment via a single LIGS.Using six unique parameters extracted from the differential pulse voltammetry(DPV)response,the machine learning-based regression provides a coefficient of correlation with 0.998 and is able to correctly predict the total and individual concentrations in complex river samples.Hence,this work provides a guide for the preparation and application of LIGS via facile and cost-efficient mass production and the development of an intelligent sensing platform based on the ANN model.
基金financial supports from National Natural Science Foundation of China(No.62205172)Huaneng Group Science and Technology Research Project(No.HNKJ22-H105)Tsinghua University Initiative Scientific Research Program and the International Joint Mission on Climate Change and Carbon Neutrality。
文摘Laser-induced breakdown spectroscopy(LIBS)has become a widely used atomic spectroscopic technique for rapid coal analysis.However,the vast amount of spectral information in LIBS contains signal uncertainty,which can affect its quantification performance.In this work,we propose a hybrid variable selection method to improve the performance of LIBS quantification.Important variables are first identified using Pearson's correlation coefficient,mutual information,least absolute shrinkage and selection operator(LASSO)and random forest,and then filtered and combined with empirical variables related to fingerprint elements of coal ash content.Subsequently,these variables are fed into a partial least squares regression(PLSR).Additionally,in some models,certain variables unrelated to ash content are removed manually to study the impact of variable deselection on model performance.The proposed hybrid strategy was tested on three LIBS datasets for quantitative analysis of coal ash content and compared with the corresponding data-driven baseline method.It is significantly better than the variable selection only method based on empirical knowledge and in most cases outperforms the baseline method.The results showed that on all three datasets the hybrid strategy for variable selection combining empirical knowledge and data-driven algorithms achieved the lowest root mean square error of prediction(RMSEP)values of 1.605,3.478 and 1.647,respectively,which were significantly lower than those obtained from multiple linear regression using only 12 empirical variables,which are 1.959,3.718 and 2.181,respectively.The LASSO-PLSR model with empirical support and 20 selected variables exhibited a significantly improved performance after variable deselection,with RMSEP values dropping from 1.635,3.962 and 1.647 to 1.483,3.086 and 1.567,respectively.Such results demonstrate that using empirical knowledge as a support for datadriven variable selection can be a viable approach to improve the accuracy and reliability of LIBS quantification.
基金financial support from The University of Manchester to cover his PhD tuition fees for him to carry out this workChina National High-end Foreign Experts Recruitment Plan Project (G2023018001L) for partially supporting the work。
文摘Electrochemical production of hydrogen from water requires the development ofelectrocatalysts that are active,stable,and low-cost for water splitting.To address these challenges,researchers are increasingly exploring binder-free electrocatalytic integratedelectrodes (IEs) as an alternative to conventional powder-based electrode preparation methods,for the former is highly desirable to improve the catalytic activity and long-term stability for large-scale applications of electrocatalysts.Herein,we demonstrate a laser-inducedhydrothermal reaction (LIHR) technique to grow NiMoO4nanosheets on nickel foam,which is then calcined under H2/Ar mixed gases to prepare the IE IE-NiMo-LR.This electrode exhibits superior hydrogen evolution reaction performance,requiring overpotentials of 59,116 and143 mV to achieve current densities of 100,500 and 1000 mA·cm-2.During the 350 h chronopotentiometry test at current densities of 100 and 500 m A·cm-2,the overpotentialremains essentially unchanged.In addition,NiFe-layered double hydroxide grown on Ni foam is also fabricated with the same LIHR method and coupled with IE-NiMo-IR to achieve water splitting.This combination exhibits excellent durability under industrial current density.The energy consumption and production efficiency of the LIHR method are systematicallycompared with the conventional hydrothermal method.The LIHR method significantly improves the production rate by over 19 times,while consuming only 27.78%of the total energy required by conventional hydrothermal methods to achieve the same production.
基金supported by the National Key Research and Development Project(Grant No.2018YFC2001100).
文摘The matrix thermal properties have an important impact on laser-induced plasma,as the thermal effect dominates the interaction between ns-pulsed laser and matter,especially in metals.We used a series of pure metals and aluminum alloys to measure plasma temperature and electron density through laser-induced breakdown spectroscopy,in order to investigate the effect of matrix thermal properties on laser-induced plasma.In pure metals,a significant negative linear correlation was observed between the matrix thermal storage coefficient and plasma temperature,while a weak correlation was observed with electron density.The results indicate that metals with low thermal conductivity or specific heat capacity require less laser energy for thermal diffusion or melting and evaporation,resulting in higher ablation rates and higher plasma temperatures.However,considering ionization energy,thermal effects may be a secondary factor affecting electron density.The experiment of aluminum alloy further confirms the influence of thermal conductivity on plasma temperature and its mechanism explanation.
基金financially supported by the National Key R&D Program Projects of China (No.2021YFB3202402)National Natural Science Foundation of China (No.62173321)。
文摘Rapid online analysis of liquid slag is essential for optimizing the quality and energy efficiency of steel production. To investigate the key factors that affect the online measurement of refined slag using laser-induced breakdown spectroscopy(LIBS), this study examined the effects of slag composition and temperature on the intensity and stability of the LIBS spectra. The experimental temperature was controlled at three levels: 1350℃, 1400℃, and 1450℃. The results showed that slag composition and temperature significantly affected the intensity and stability of the LIBS spectra. Increasing the Fe content and temperature in the slag reduces its viscosity, resulting in an enhanced intensity and stability of the LIBS spectra. Additionally, 42 refined slag samples were quantitatively analyzed for Fe, Si, Ca, Mg, Al, and Mn at 1350℃, 1400℃, and 1450℃.The normalized full spectrum combined with partial least squares(PLS) quantification modeling was used, using the Ca Ⅱ 317.91 nm spectral line as an internal standard. The results show that using the internal standard normalization method can significantly reduce the influence of spectral fluctuations. Meanwhile, a temperature of 1450℃ has been found to yield superior results compared to both 1350℃ and 1400℃, and it is advantageous to conduct a quantitative analysis of the slag when it is in a “water-like” state with low viscosity.
基金support from the National Natural Science Foundation of China(Nos.52075246 and U2341264)the Natural Science Foundation of Jiangsu Province(Nos.BK20211568 and BZ2023045)+2 种基金National Science and Technology Major Project of China(No.J2019-Ⅲ-0010-0054)Fundamental Research Funds for the Central Universities(No.NE2022005)Liaoning Provincial Key Laboratory of Aircraft Ice Protection(No.XFX20220301).
文摘The excellent performance of laser-induced removal has been widely recognized,yet the limitation of its applications has been gradually approached for complex multilayer coatings in practical situations.Therefore,it is necessary to clarify the laser-induced removal mechanisms of different material layers,which may contribute to guiding precise and controllable layer-by-layer removal and subsequent repair.Herein,the laser-induced layer-by-layer removal of FeCo-based multilayer wave-absorbing coatings was designed and verified.The macro/micro morphologies and elemental analysis indicated that the removal of the topcoat and wave-absorbing layer was dominated by thermal ablation.Interestingly,experiments and simulations demonstrated that a shift in the removal mechanism,i.e.,from the ablation mechanism to the stripping mechanism,occurred when the laser irradiated the primer.It is mainly attributed to the competing contributions of temperature rise and thermal stress to the removal effect.Subsequent macrodynamic behavior captured by a high-speed camera also validated the combination of both re-moval mechanisms.Additionally,the evolution of the crystalline phase and element valence state was revealed.Further laser-induced breakdown spectroscopy revealed the microscopic material motions dur-ing the layer-by-layer removal,including molecular bond breaking induced by multiphoton absorption,atomic ionization,excitation and compounding of electrons and ions,crystal lattice deformation caused by electron-phonon coupling,etc.Based on the above analysis,the thermo-mechanical action mechanisms and microscopic motion models of laser-induced layer-by-layer removal for FeCo-based multilayer wave-absorbing coatings were established,which is expected to be an ideal method for breaking through the limitation of laser-induced removal’s applications.
基金The National Natural Science Foundation of China(Grant Numbers:U21A20135 and 52205488)‘Shuguang Program’supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission(Grant Number:20SG12)Shanghai Jiao Tong University(Grant Number:2020QY11).
文摘Surface-enhanced Raman spectroscopy(SERS)microfluidic system,which enables rapid detection of chemical and biological analytes,offers an effective platform to monitor various food contaminants and disease diagnoses.The efficacy of SERS microfluidic systems is greatly dependent on the sensitivity and reusability of SERS detection substrates to ensure repeated use for prolonged periods.This study proposed a novel process of femtosecond laser nanoparticle array(NPA)implantation to achieve homogeneous forward transfer of gold NPA on a flexible polymer film and accurately integrated it within microfluidic chips for SERS detection.The implanted Au-NPA strips show a remarkable electromagnetic field enhancement with the factor of 9×108 during SERS detection of malachite green(MG)solution,achieving a detection limit lower than 10 ppt,far better than most laser-prepared SERS substrates.Furthermore,Au-NPA strips show excellent reusability after several physical and chemical cleaning,because of the robust embedment of laser-implanted NPA in flexible substrates.To demonstrate the performance of Au-NPA,a SERS microfluidic system is built to monitor the online oxidation reaction between MG/NaClO reactants,which helps infer the reaction path.The proposed method of nanoparticle implantation is more effective than the direct laser structuring technique.It provides better performance for SERS detection,robustness of detection,and substrate flexibility and has a wider range of applications for microfluidic systems without any negative impact.
基金the Natural Science Foundation of China(No.22105218).
文摘It is challenging to cooperatively improve the nonlinear optical(NLO)efficiency and the laser-induced damage threshold(LIDT).This work reports a novel IR NLO materials CsInP_(2)S_(7)(CIPS)designed by combination the strategies of alkali metals substitution and microscopic NLO units PS4 introduction based on AgGaS_(2).CIPS was composed of strongly distorted[InS_(6)]^(9-)octahedra and[P_(2)S_(7)]4-dimers constructed by corner-sharing[PS_(4)]^(3-),which increase the NLO efficiency and decrease thermal expansion anisotropy simultaneously.Compared with AgGaS_(2),CIPS exhibited strong phase matchable NLO response ca.1.1×AGS@2.1μm,high LIDT ca.20.8×AgGaS_(2),and IR transparency up to 15.3μm.Structural analysis and theoretical investigation confirmed that large SHG effect and ultrahigh LIDT of CIPS originated from the synergistic contribution of[InS_(6)]^(9-)octahedra and[P_(2)S_(7)]4-dimers.These results indicate that CIPS is a promising NLO candidate in the mid-IR region,and this study provides a new approach for developing potential NLO-LIDT compatible materials.
文摘Two-dimensional diagnosis of laser-induced zirconium(Zr)plasma has been experimentally performed using the time-of-flight method by employing Faraday cups in addition to electric and magnetic probes.The characteristic parameters of laser-induced Zr plasma have been evaluated as a function of different laser irradiances ranging from 4.5 to 11.7 GW cm-2 at different axial positions of 1–4 cm with a fixed radial distance of 2 cm.A well-supporting correlation between the plume parameters and the laser-plasma-produced spontaneous electric and magnetic(E and B)fields was established.The measurements of the characteristic parameters and spontaneously induced fields were observed to have an increasing trend with the increasing laser irradiance.However,when increasing the spatial distance in both the axial and radial directions,the plasma parameters(electron/ion number density,temperature and kinetic energy)did not show either continuously increasing or decreasing trends due to various kinetic and dynamic processes during the spatial evolution of the plume.However,the E and B fields were observed to be always diffusing away from the target.The radial component of electron number densities remained higher than the axial number density component,whereas the axial ion number density at all laser irradiances and axial distances remained higher than the radial ion number density.The higher axial self-generated electric field(SGEF)values than radial SGEF values are correlated with the effective charge-separation mechanism of electrons and ions.The generation of a self-generated magnetic field is observed dominantly in the radial direction at increasing laser irradiance as compared to the axial one due to the deflection of fast-moving electrons and the persistence of two-electron temperature on the radial axis.
