We demonstrate that the filamentation process is strongly influenced by the polarization state of the driver laser. When the laser polarization changes from linear to circular, the critical power for the self-focusing...We demonstrate that the filamentation process is strongly influenced by the polarization state of the driver laser. When the laser polarization changes from linear to circular, the critical power for the self-focusing of a Ti:Sapphire laser(800 nm, 40 fs) in air increases from about 9.6±1.0 to 14.9±1.5 GW, while the second nonlinear refractive index n_2 of air decreases from 9.9 × 10^(-20) to 6.4 × 10^(-20) cm^2∕W. We also demonstrate that the luminescence from the neutral nitrogen molecules at 337 nm is dependent on both the laser intensity and plasma density inside the filament.展开更多
The development and construction of Ultra Super Critical(USC) fossil fired power plants and advanced nuclear power plants are the most important and effective issue to improve national electricity structure in China a...The development and construction of Ultra Super Critical(USC) fossil fired power plants and advanced nuclear power plants are the most important and effective issue to improve national electricity structure in China and to fulfill the national emission aim which had been proposed and promised.Further, steel technology is one of the most imperative fundamentals to ensure the development and construction of USC fossil fired power plants and advanced nuclear power plants.This paper briefly introduced the state-of-the -art and achievement of steel technology used for USC fossil fired power plants and advanced nuclear power plants in China so far.Meanwhile,the authors also analyzed and discussed the potential research and development plans of the important steel technology in China in the near future.展开更多
Near-IR(wavelength≈1μm)laser ablation of bulk,chemically-inert gold in water was compared for different laser pulse width in broad the range of 300 fs–100 ns,comparing a number of key ablation characteristics:mass ...Near-IR(wavelength≈1μm)laser ablation of bulk,chemically-inert gold in water was compared for different laser pulse width in broad the range of 300 fs–100 ns,comparing a number of key ablation characteristics:mass loss,singleshot crater volume and extinction coefficient of the generated colloidal solutions taken in the spectral ranges of interband transitions and localized plasmon resonance.Comparing to related air-based ablation results,at the given fluences laser ablation in the liquid resulted in the maximum ablation yield per unit energy and maximum NP yield per pulse and per unit energy for the picosecond lasers,occurring at subcritical peak pulse powers for laser self-focusing.The self-focusing effect was demonstrated to yield in incomplete,effectively weaker focusing in the water filaments of ultrashort laser pulses with supercritical peak powers,comparing to linear(geometrical)focusing at sub-critical peak powers.At the other,nanosecondpulse extreme the high ablation yield per pulse,but low ablation yield per unit energy and low NP yield per pulse and per unit energy were related to strong ablation plasma screening,providing mass removal according to the well-established scaling relationships for plasma.Illustrative comparison of the ablation and nanoparticle generation efficiency versus the broad fs–ns laser pulse width range was enabled in terms of productivity,economicity,and ergonomicity,using the proposed universal quantitative criteria.展开更多
Purpose The constant work-rate to exhaustion tests must be repeated several times at each work-rate to estimate subject-level trial-to-trial variance(intra-individual variability,IIV)of critical power(CP)and work capa...Purpose The constant work-rate to exhaustion tests must be repeated several times at each work-rate to estimate subject-level trial-to-trial variance(intra-individual variability,IIV)of critical power(CP)and work capacity(W').Alternatively,these parameters and their variance can be estimated by repeating the 3-min all-out test(3MT)fewer times.The purpose of this study was to propose a method to determine subject-level repeatability of the 3MT and demonstrate the need to repeat the test multiple times to estimate IIV.Methods Seven cyclists performed a ramp test and four 3MTs on a CompuTrainer.The parameters CP,W',peak power(Pp),and total work(TW)were compared across trials using repeated measures ANOVA,Bland-Altman analysis,Intraclass Cor-relation Coefficients(ICC),Typical Error(TE)of measurement,and Coefficient of Variation(CV).Results For the group,average CP and W'were 284±58 W and 10.214±3.143 kJ.The reliability statistics,CP(ICC=0.97,TE=8 W,CV=2.94%)and W'(ICC=0.88,TE=1.11 kJ,CV=10.87%),indicated strong agreement.Subject-level repeatability was determined by comparing time-to-peak power(TPp),absolute difference in Pp(δPp),and TW(δTW)for pairs of 3MTs.The average IIVs estimated by the 95%confidence intervals were±15 W for CP and±1.68 kJ for W'.Conclusions Thresholds are proposed for TPp(7 s),δPp(10%),andδTW(3%)to determine subject-level repeatability of the 3MT before computing the IIV of CP and W'.It is suggested that the 3MT is repeated at least three times to estimate the IIV,which aids in personalized measurement of training improvements and performance optimization。展开更多
基金supported in part by the National Natural Science Foundation of China(Nos.61625501,61427816,and 61235003)the National Basic Research Program of China(No.2014CB921300)+1 种基金the Open Fund of the State Key Laboratory of High Field Laser Physics(SIOM)the Program for JLU Science and Technology Innovative Research Team(JLUSTIRT)(No.2017TD-21)
文摘We demonstrate that the filamentation process is strongly influenced by the polarization state of the driver laser. When the laser polarization changes from linear to circular, the critical power for the self-focusing of a Ti:Sapphire laser(800 nm, 40 fs) in air increases from about 9.6±1.0 to 14.9±1.5 GW, while the second nonlinear refractive index n_2 of air decreases from 9.9 × 10^(-20) to 6.4 × 10^(-20) cm^2∕W. We also demonstrate that the luminescence from the neutral nitrogen molecules at 337 nm is dependent on both the laser intensity and plasma density inside the filament.
文摘The development and construction of Ultra Super Critical(USC) fossil fired power plants and advanced nuclear power plants are the most important and effective issue to improve national electricity structure in China and to fulfill the national emission aim which had been proposed and promised.Further, steel technology is one of the most imperative fundamentals to ensure the development and construction of USC fossil fired power plants and advanced nuclear power plants.This paper briefly introduced the state-of-the -art and achievement of steel technology used for USC fossil fired power plants and advanced nuclear power plants in China so far.Meanwhile,the authors also analyzed and discussed the potential research and development plans of the important steel technology in China in the near future.
基金the Ministry of Science and Higher Education of the Russian Federation(Project No.075-152020-775)。
文摘Near-IR(wavelength≈1μm)laser ablation of bulk,chemically-inert gold in water was compared for different laser pulse width in broad the range of 300 fs–100 ns,comparing a number of key ablation characteristics:mass loss,singleshot crater volume and extinction coefficient of the generated colloidal solutions taken in the spectral ranges of interband transitions and localized plasmon resonance.Comparing to related air-based ablation results,at the given fluences laser ablation in the liquid resulted in the maximum ablation yield per unit energy and maximum NP yield per pulse and per unit energy for the picosecond lasers,occurring at subcritical peak pulse powers for laser self-focusing.The self-focusing effect was demonstrated to yield in incomplete,effectively weaker focusing in the water filaments of ultrashort laser pulses with supercritical peak powers,comparing to linear(geometrical)focusing at sub-critical peak powers.At the other,nanosecondpulse extreme the high ablation yield per pulse,but low ablation yield per unit energy and low NP yield per pulse and per unit energy were related to strong ablation plasma screening,providing mass removal according to the well-established scaling relationships for plasma.Illustrative comparison of the ablation and nanoparticle generation efficiency versus the broad fs–ns laser pulse width range was enabled in terms of productivity,economicity,and ergonomicity,using the proposed universal quantitative criteria.
文摘Purpose The constant work-rate to exhaustion tests must be repeated several times at each work-rate to estimate subject-level trial-to-trial variance(intra-individual variability,IIV)of critical power(CP)and work capacity(W').Alternatively,these parameters and their variance can be estimated by repeating the 3-min all-out test(3MT)fewer times.The purpose of this study was to propose a method to determine subject-level repeatability of the 3MT and demonstrate the need to repeat the test multiple times to estimate IIV.Methods Seven cyclists performed a ramp test and four 3MTs on a CompuTrainer.The parameters CP,W',peak power(Pp),and total work(TW)were compared across trials using repeated measures ANOVA,Bland-Altman analysis,Intraclass Cor-relation Coefficients(ICC),Typical Error(TE)of measurement,and Coefficient of Variation(CV).Results For the group,average CP and W'were 284±58 W and 10.214±3.143 kJ.The reliability statistics,CP(ICC=0.97,TE=8 W,CV=2.94%)and W'(ICC=0.88,TE=1.11 kJ,CV=10.87%),indicated strong agreement.Subject-level repeatability was determined by comparing time-to-peak power(TPp),absolute difference in Pp(δPp),and TW(δTW)for pairs of 3MTs.The average IIVs estimated by the 95%confidence intervals were±15 W for CP and±1.68 kJ for W'.Conclusions Thresholds are proposed for TPp(7 s),δPp(10%),andδTW(3%)to determine subject-level repeatability of the 3MT before computing the IIV of CP and W'.It is suggested that the 3MT is repeated at least three times to estimate the IIV,which aids in personalized measurement of training improvements and performance optimization。
